Understanding Ionic and Covalent Compounds

We can take melting points, melting and boiling points. Melting and boiling points. How will they be? High. Right? Why? Because these two depend on force of attraction. Where force of attraction will be more, what are melting and boiling points? High. And in ionic compounds, there are opposite ions, so definitely force of attraction will be very strong. So how will the melting and boiling points be? They will be high. Okay. Next comes electrical conductivity. Electrical conductivity. Hmm? Huh? Electrical conductivity is negligible. Electrical conductivity is negligible for ionic compounds. When they dissolve in water, they conduct. That's it. They conduct in a molten state. Will any ionic compound conduct in a solid state? Electricity? Prince? Where were you lost? What were you thinking? The question I asked, were you thinking? Did you think? Answer me. In a solid state, no ionic compound will conduct electricity? Sit. Sit. Look, in a solid state, an electrical conductor will not be there. Why? Because conduct... To conduct electric current, it is important to have a charge move. Right? Rate of movement of charge. If there is an electron but it is not able to move, then there will be no conductivity. If there is an ion but it is not able to move, then there will be no conductivity. So when we talk about solid state, then what will remain in an ionic compound in a solid state? It is a very strong force of attraction. So ions will hold each other so strongly that they will not let each other move. And there will be no conductivity. But if you have... Convert to what? Molten state. Molten state means you have heated it and melted it. What will happen by melting? Force of attraction will become weak. Ions will become distant. Now it will be able to move and the compound or substance will show conductivity. So either convert it to molten state or convert it to its aqueous solution. Aqueous solution means you have put it in water. Even after pouring it in water, what happens to ions? Separate. It will become a solution. Then, if you put an electrode and complete the circuit, then the current will flow. So, in the molten state or aqua solution, any ionic compound will be a good conductor of electricity. In the solid state, it will not conduct electricity. If it is in the pure state. But if there is any impurity in it, All the dropper children, remember the solid state a little bit. We read defects. So if there is an impurity in its crystal, if another foreign atom comes, then it may be due to that that conductivity shows. But if we talk about general condition, then that conductivity will not show in solid state. Conductivity will show in the form of molten and aqueous solution. Conductivity will show in the form of molten and aqueous solution. Is this clear? Are you writing along? It is not looking. You have to remind yourself every time that you should write. Write it together. Or you become a mantra-free by looking at me. That you forget. You just keep looking at me like this. Okay. Fifth. Fifth property is solubility. Solubility. Think and tell me. In which type of solvent are ionic compounds dissolved? In which type? In polar. For example, the most common polar solvent is water. And in non-polar? Are they dissolved in non-polar? No, they are not. First of all, think about whether you understand the term polar or non-polar. Because we have already studied it. I have taught you polar and non-polar in periodic table. Twice. So, is the picture working in your mind as soon as you hear the word polar? Polar means, there are two poles, electric poles, one positive and one negative. So, wherever there is charge separation, whether it is partial or complete charge separation, it is called polar. Two poles are formed, one positive and one negative, the charges are separated. And where there is no charge separation, it will become non-polar. So, the solvents in which we dissolve things, we have divided them into two categories, polar and non-polar. Polar solvent is the one which has charge separation. Non-polar is the one which does not have charge separation. Now, on what does charge separation depend? It depends on their difference in electronegativity. Do you remember that example of pulling a rope? Electronegativity. If someone has a lot of electronegativity, then he will pull the electron towards himself. That side will become negative and the other side will become positive. If both have the same electronegativity or almost the same, then the electron will not go anywhere. In that case, how will the molecule be? Non-polar. You have studied it, right? Yes? So, what is there in these ionic compounds? Are the charges separate or not? Is there a charge separation in ionic compounds or not? There is one positive and one negative. Negative is like you took NaCl, so NaCl has Na plus and Cl minus. In this charges are separate, complete separation is there. So in chemistry there is an aphorism, there is a saying in chemistry, it is said like dissolves like. Have you heard in childhood, like dissolves like. Like dissolves like means, whatever is there, it will dissolve in that. So if it has charge separation, i.e. it has a polar nature, then in which type of solvent will it dissolve? The one which is also polar. Like dissolves like. And what will remain in non-polar? Insoluble. Are you understanding this basic concept? Yes? So because in ionic compound there is charge separation, in which will it dissolve? They get dissolved or they are soluble in polar solvents. They are soluble in Polar Solvents The best example of Polar Solvents is water I have explained to you many times that what is in water? It is this condition There is a huge difference between Oxygen and Hydrogen in Electronegativity So, due to this, Oxygen becomes negative and Hydrogen becomes positive This becomes Polar Now, imagine this whole thing You have put NaCl in water There is water all around So, what will happen? Water. This is? Who will come near this? The end of oxygen. Who will come near this? The hydrogen one. I have already explained it. So who is surrounding this? Water from the side of oxygen. Water is coming from the side of oxygen. And who is coming near CL minus? The side of hydrogen. It is interactive. interacting with water. What is it doing with water? It is interacting with water. Now the force of attraction between them, will be more than this force of attraction. Me and Himani have held hands, we both have force of attraction. Now many people are pulling me from behind, many people are pulling him from behind. This is the situation. So our force of attraction will come to a point and break. Because this surrounding force of attraction, what will it do? It will overpower, it will overcome. As soon as this happens, their force of attraction breaks and these two will be different. As soon as they are different, that compound will be dissolved in water. Is this point coming to your understanding? Okay. This capacity, this tendency of any solvent to separate the charges. The capacity of a solvent, the tendency of a solvent to separate the charges is called The capacity of any solvent, someone can do this very well to separate the charges and someone can do it a little less, someone can do it a little less, someone can do it a little less, but they can't do it at all. Everyone's solvent nature is different, right? So, the capacity of any solvent to separate the charges, to dissolve things in itself, what is this property? Hydration is a process. This process is known as hydration. To interact with water is hydration. Addition of water is hydration. We say we are feeling dehydrated. There is a lack of water. The other person says drink water and you will be hydrated. Hydration. Taking in water, contact with water, interaction with water. That's the process. Any solvent's capacity to separate the charges is its dielectric constant. Dielectric constant. Have you ever heard this term? Have you heard? Dielectric constant. What is dielectric constant? The tendency of a solvent to separate the charges. Whose dielectric... The more the dielectric constant, the more it can easily separate the charges and things can dissolve better. Water's dielectric constant is very high, 82. That's why maximum things get dissolved in water. We say water is the universal solvent. Because it dissolves maximum things. Are you getting the point? Yes? So write dielectric constant for those who don't know. Dielectric constant is what? It is the tendency of a solvent to separate charges. The capacity to separate charges of any solvent is its dielectric constant. Now, let's combine these two points. The ionic compound will be dissolved in a solvent which is polar and whose dielectric constant is high. You understand this process, there are two things happening in this. First, these two are getting attracted. Why? Because there is a charge in this and there is a charge in this. That means both are polar. Because both are polar, what will they do at the opposite ends? They will get attracted. then it will be engulfed by water. If it is not polar, then there will be no interaction between these two. Then the second step will be that their attraction will increase so much that they will separate. This is the point. Are you understanding this point? There are two processes. First, it is engulfing with water and interacting with it. And then water is pulling it so much because its dielectric constant is high. What is it doing to both the ions? Separate. then that compound dissolves in water. Are you getting this point? Yes? So what will we say? Ionic compounds are soluble in those solvents which are polar and which have high dielectric constant. Like water. Is this point coming to your mind? If there is an organic solvent whose dielectric constant is moderate, then also the ionic compound will dissolve. Like methyl alcohol. CH3OH, its dielectric constant is around 32. So some of the ionic compounds get dissolved in it. But if you have ether, you have benzene, you have CCL4, which is completely non-polar, then ionic compounds won't get dissolved in it. So a solvent which has polarity and whose dielectric constant is high, the ionic compound will get dissolved in it. Do you understand this point? This process, interaction with water, is called hydration. Interaction of a compound with water is called hydration. Now think and tell me, will energy be required or released in this process? Will energy be required or released in this hydration process? Will it be required? Because the force of repulsion is more than the attraction. I have explained you the basic concept. Where the attraction is more, the energy will be released. Where the repulsion is more, the energy will be required. Now think and tell me. Is the attraction going on here or is the repulsion running far or is it coming near? Then energy will be released. There is a... force of attraction between water and that ionic compound, isn't it? This attraction is not visible. O minus minus minus Na plus. H plus plus plus plus Cl minus. Attraction is happening, isn't it? And this force of attraction is increasing. That's why that compound is dissolving. Otherwise, it doesn't break. Yes, so energy will be released in this. And every energy has a name. What will be its name? Hydration Enthalpy Hydration Energy So the process is Hydration And the amount of energy That is being released in this Will be the Hydration Enthalpy Some will have less Some will have more Now the solubility of that compound will depend on this hydration enthalpy. It will depend on lattice enthalpy as well as on hydration enthalpy. So write it down. This process of interaction of water and ionic compound is known as hydration. And the amount of energy released is called hydration enthalpy. The amount of energy released during hydration is called hydration. Enthalpy. Who's class is after my class? In your batch? It's everyday. Okay, after my class, it's always physics. So physics happens in the morning and then repeats. Is there any doubt at any point? Hydration enthalpy is the amount of energy released during hydration of a compound. Amount of energy released during hydration of a compound. Write it with your head up. Everyone's eyes will get damaged. If you're having fun. Yes. Your eyesight will get weak. Keep your head up a little. Clear till here? Next property, which type of reactions will ionic compounds show? Obviously ionic reactions. One is the reaction in which atoms and molecules participate, another is the reaction in which ions participate. So of course, which will be the reactions of ionic compounds? Ionic reactions in which ions participate. For example, you took NaCl's Aqua solution and mixed it with AgNO3's Aqua solution. Have you ever read this reaction? You made Aqua solution in two test tubes and then mixed it. So, as soon as you make Aqua solution, will this process work? And in which one will it be broken? In Na plus and Cl minus. This will also be broken in Ag plus and... NO3 minus. Now, in which reaction is it happening? It is happening in ions. There are no atoms and molecules. So, what type of reaction will this be? Ionic reaction. And ionic reactions are very fast reactions. As soon as you mix these two, AGCL's white PPT will be formed. As soon as you mix it, it won't take long at all. Whereas, if there are atoms and molecules in the reaction, i.e. if there is a molecular reaction or a covalent reaction, then it takes some time. Because first, their bonds break. Then new bonds are formed. There is no such problem in this. Bond breaking happened in the first aqua solution itself. Their bonds have been broken in their own aqua solution. Now, it is just bond formation. As soon as they mix, they will attract. As soon as they attract, they will form a compound. So, the ionic compounds show ionic reactions which are very fast. Those which have very fast reactions. Have you ever read the term isomers or isomerism? Do you remember what isomerism is? You have heard of it but you don't remember. Why don't you guys recall what you read? You didn't have to spend a lot of time reading it. It's been a long time since you were studying, right? Why can't you recall? This problem is with everyone. You can't recall. Why can't you recall? You are studying, you are working hard, but still you can't recall. This is heart-wrenching. You are studying, but at the time you should remember, when it is needed, you are not remembering. Iso-mers. Many things are self-explanatory. You don't pay attention. You are just reading, but you are not reading mindfully. Every name explains itself. Your name must have some meaning, right? Like my name means Punam. Punam ka jaan. It means, right? Isomers. Isotopes, isobars, isotones, isoelectronic species. Iso-diafers, isosters, isomorphs, isomers, iso, iso, iso, iso, iso, iso means? Something or the other. Mers, monomer, polymer, monomer, dimer, trimmer, mer, mer, mer, mer. Dimer, dimer means? Two molecules, two units. Trimer, three units. Monomer? Polymer. So what does mer mean? Molecules, units. Iso means same, mer means units. Such compounds whose molecules are same. Such compounds whose molecular formula is same. But somewhere or the other, some property will be different, so there will be different compounds. Relate things like this. Study them mindfully. Or make some writing trick. Or if you know the meaning of it, then you will remember it. So isomer means compounds whose molecular formula is the same but some property varies between them. That's why they are different compounds. Now when we talk about ionic compounds, they don't show isomerism. Ionic compounds don't show isomerism. You will understand this better when you study isomerism in organic. If you study Stereo-Isomerism and Structural then you will understand better. Now the most important point that I want to explain to you is that Isomerism does not show and why it doesn't show? Very very important because there is no direction of the ionic compound. There is no direction of ionic bond. Ionic bond is non-directional. You have to take some basics along with you, otherwise it will be very difficult for me to explain everything. You guys are so blank that I have to start everything from zero. I think bond is non-directional. What does this mean? Any direction of it, like covalent bond. What is there in covalent bond? Overlapping. What is there in covalent bond? Overlapping. S-S, S-P, P-P, P-D, there is overlapping. Overlapping means two things are overlapping each other. This will always be in direction. X direction, Y direction, Z direction. Overlapping will occur on an axis. It will be on a coordinate. It will be in X direction, Y direction, Z direction, X and Y direction. So, there will be a direction of covalent bond. Ionic bond has an ion. How is its electric field? It is uniform. It is not on the X axis or Y axis. So it has a uniform electric field. What did it do because of uniform electric field? It attracted opposite ions from all sides. Is there any direction? No. When there is no direction, if you lift the CL-here and do it from here, then there will be no difference. Are you getting this point? So, Ionic compounds don't show isomerism. Why? Because there is no direction of the bond. There is a difference in covariance. Because there is a direction. If you put someone from here to there, there will be a difference. Are you getting this point? Yes? So, what will you write in the next property? They do not show, Ionic compounds do not show isomerism. Ionic compounds do not show isomerism. Why? Because ionic bond is non-directional. Ayanic bond is non-directional. Ayanic bond is non-directional. Tell me the truth, how many kids watch mobile phones before going to bed? Tell me the truth, be honest. I am not going to buy your mobile phone. How many kids watch mobile phones before going to bed? This is one of the reasons why your recalling power is low. There is a technique called 321. The 321 technique is used to increase your memory. and recalling power. Both of them have to be increased. So, you apply this technique. What is this technique? Three hours before sleeping. Three. Three hours before. Anything. That means, the food you want to eat is to be eaten three hours before. After that, you don't want to eat. Three. Two. Two hours before sleeping. Two hours before sleeping. What do you have to do? Any relaxing, meditation, anything. Close your eyes and sit. Bring some positive thoughts. And one hour before sleeping, keep all your gadgets away. Whether it's a laptop, phone or TV. After that, one hour after that, you sleep. This will work magically. Keep all your gadgets away one hour before. What do you do? You keep them away one minute before. After looking at the phone, Facebook, Instagram, YouTube, Reels. And then, now I will get a good sleep. Sleep will be good. But it will go in the brain. So, your memory and recalling will go down. Over the period of time. What? Should I tell you again? Eat food 3 hours before going to sleep and then don't eat anything. Digestion is for you. You are a child of bio, you understand the process of digestion. What to do 2 hours before? Some positive thoughts. Talk to your parents. You can get positivity from anywhere. Right? Like I said one day, listen to instrumental music. Or talk to your parents. If they know meditation, then do some meditation. And 1 hour before, turn off all gadgets. Screen off. Then sleep. These are not my mind-blowing stories that I tell you. All this is scientifically proven. Yes, you can watch gadgets an hour before. Close it. Sleep after an hour. So if you want to sleep at 11, then close your phone at 10. TV, phone, laptop, PC, VC. Close everything. Okay? Yes. Video lecture, first watch it, then read it from the book. It is not necessary to watch video lecture before sleeping. It is not necessary. If you watch video lecture during the day, then if you want to practice something, then do that. Do it from the book, read it from the notes. Okay, so these were the properties of ionic compounds. Now, let's discuss a small topic which is important also. Variable Electrovalency. Variable Electrovalency. This is important. Variable electrovalency. Do you remember electrovalency? The valency in the ionic compound will become electrovalency. Variable means which is not fixed. Which changes. Like you must have read iron. Iron compound FECL2 and FECL3 is also formed. FEO is also formed. FECL2 is also formed. So if we talk about valency in this, So, if we talk about the oxidations, then how much is going on in this? Plus 2, how much is going on in this? Plus 3. Another common example is copper. What does copper show? It also shows the valency of plus 1 and plus 2. This is more stable in both. And maybe you have heard of tin. Tin also shows plus 2 and plus 4. Lead is present. Lead also shows plus 2 and plus 4. Thallium is there. Thallium also shows 1 and 3. Right? Bismuth is there. Bismuth also shows 3 and 5. So, a lot of metals, especially those of D block, especially DK, PK, all of these show wearable valency. They have wearable electrovalency. Okay? What are the reasons? If we discuss about iron, what are the reasons? Electronic configuration, very good. What is the electronic configuration of Fe? Fe is 3d6 4s2. 26 atomic number. What is the configuration? 3d6 4s2. What is valency? You must have studied in your childhood, you get valency on the basis of the electrons in the outermost shell. So how many electrons are there in its outermost shell? Two. If in the outermost shell, we have read in periodic also, if there are 1, 2 or 3 electrons in the outermost shell, then that is its valency. How many 2 are there in its outermost shell? So its valency is also 2, justified. But what is it showing along with 2? It is also showing 3. Why? Because if it loses one more electron from here, then its configuration will be 3D5 and it will be half-filled and hence more stable. Top! By formula, by default, plus 2 will show. It will definitely show. But what does it show along with it? Plus 3. And what is its configuration in plus 3? 3D 5, which is more stable. That's why its compounds in plus 3 are more stable. Tell me about copper. What is the configuration of copper atom? 3D 10 4S 1. This is copper, right? So, there is one electron in the outermost. Valency 1 can come. Justified. Why this? When after losing one electron, it is fulfilled. If it loses one electron, it will show the valency of plus 1. So, it is fulfilled. And fulfilled means stable. So, why it loses one more electron and makes it plus 2? It is more stable than plus 2 plus 1. It is more stable than plus 2 plus 1. Whereas in this, its configuration is 3D10 In this, its configuration is 3D9 If you apply the concept of electronic configuration, then it should be stable It should not be made But this is more stable Why? What? What is the reason for this? Yes Yes, very good Where is all this being made? It is being made in the Aqua solution Where will the ion be made? It will be formed in the Aqua solution. What is working in the Aqua solution? Hydration. What energy is working? Hydration, Enthalpy. Now understand this. Its size has become small. The more the positive charge increases, the smaller the size of the ion. So what has become its size? Small. Its charge has become more magnitude wise. Plus 1, plus 2. So the charge has increased and the size has become small. So overall charge density has increased. As the charge density increases, its electric field becomes stronger. It interacts with water more. Hydration enthalpy increases. And the more energy is released, the more stability the system gets. Do you understand this point? So although it is less stable in configuration, but it has high hydration enthalpy. And that's why What will be more stable than the state of plus 2 plus 1? Clear? Tell me about all these. All these are of the same type. All these have the same reason. See, how much difference is there between these? See, in these... 3. Who said 3? In these... In all these, the oxidation state is differing from 2 to 2. Right? The reason here seems to be... That is called inert pair effect. The reason here is inert pair effect. Important. Okay. Now, which family does tin belong to? Which family does tin belong to? Carbon. Under carbon, nitrogen. Nitrogen comes like this. Carbon, silicon, germanium, tin, lead, and flavorium. Right? So, carbon, silicon, germanium, tin, and lead. They are coming in the same family. Where is this coming from? Boron family. Right? Boron. Aluminium, Gallium, Indium, Thallium. This is Thallium. This is Nitrogen family. Nitrogen, Phosphorus, Arsenic, Antimony, Bismuth. You see one thing common in all of them. These are lower elements. These are not the upper elements, these are the lower elements. The lower elements means they are heavy. The lower mass is more, right? These are heavy elements. And which group are they from? Group 13. 14, 15. We are in P block. Group 13, 14, 15. And below, 6th period, 7th period. Now, remember the table. Group 13, 14, 15. 6th period, 7th period. Who is coming before them? D and F. Right? Before them... When this is filled, when Indium Thallium is filled, then Lanthanides Actonides will be filled and then this will be filled. Same for this, same for this. So before this, D and F are filled. That means transition series is filled, Lanthanides Actonides are filled. And whenever inorganic is talked about Lanthanides Actonides, one common reason will be Lanthanide contraction, poor shielding effect. All the reasons revolve around this. So, how is the screening of D and F electrons? Poor. How is the shielding effect of D and F electrons? Poor. So, the D and F electrons which are before this, are not able to shield the nuclear charge, so the nuclear force of attraction on them must have increased. Z-effective, remember. What will be Z-effective for them? More. Now see, what is the configuration of the carbon family? Tell me. Carbon family's configuration is outermost. NS2NP2 Right? Before this, what is the boron family? NS2NP1 What is the nitrogen family? NS2NP3 Right? Where N is the balance shell. Now, how many electrons are there in its balance shell? 3 That's why valency 3 is also coming. How many electrons are there in its valence shell? 4 So, valency 4 is also coming. How many electrons are there in its valence shell? 5 So, valency 5 is also coming. This is what should come in the normal configuration. But, because Z-effective has increased, because nuclear force of attraction has increased, so it must have increased so much that these electrons with S will become inert. Because it is being attracted by the nucleus. And this is always a pair of electrons. That pair of electrons is becoming inert. So what is the name? Inert pair effect. Inert means that it will not be able to participate in the bond formation. When it will not be able to participate, then its valency is 1, 2, 3. So, their valency will be less than 2 units because these NS2 electrons are not participating. Did you understand this effect? Sure. Let me repeat it once. Where will this group 13-14 be? Now write the small points. Inert pair effect. Where will it show? It decreases a little in group 15 but it shows very well in group 13-14. So, it will be applied in group 13-14-15. And in 13, 14, 15, heavier elements will be applied. So inert pair effect is applicable to heavier elements of group 13, 14, 15. Inert pair effect is applicable to heavier elements of group 13, 14, 15. Okay? And what is happening? Due to poor shielding effect of D and F electrons, due to poor shielding effect of D and F electrons, Z effective on these elements increases. Due to poor shielding effect of D and F electrons, Z effective on these elements increases due to which due to which the ns pair of electron due to which the ns pair of electrons the ns pair of electrons become inert. Hence their electrovalency decreases by 2 units. Hence, their electrovalency decreases by 2 units. Did you understand? So, boron family plus 1 plus 3. This will show carbon family plus 2 plus 4. And nitrogen family plus 3 plus 5. Which one will be more stable? Suppose you are asked to decide. Is lower more stable or higher more stable? Lower. Lower is more stable. If the compound of tin is SNCl2 and SNCl4, which one is more stable? This one. So, the lower valency will be more stable. Is it clear? Has everyone got CPP? Not today? Okay, but today, what will happen? There will be Lewis structures. Okay, so what has been completed here? Ionic bond. How was Ionic bond made? By transfer of electron. What was the second method of making a bond? There were three methods. One method was complete transfer. Second method was equal sharing. Third method was unequal sharing. So we completed the first method. Bond was made, compound was made, property was studied. Now the second method is equal sharing of electron. Maximum questions will come from here. Covalent bond. Covalent. Co means together. Coordinate. Co-operate. Similarly, covalent. Valent, valency. Bond formation. They are helping each other by equal sharing of electrons. So how is covalent bond made? Covalent bond is formed by equal sharing of electrons. Now when will it be made? When will this happen? Suppose there are non-metals and non-metals. Right? One is Cl and the other is Cl. What is the tendency of both of them to gain electrons? Non-metals are electronegative. There is no donor. There is no one to give. So they don't have the option of taking. But they have to be stable. They are unstable. So what will they do for that? They will share their electrons equally. If we make the lowest symbol, how will it be? How many dots should I put? Seven. One, two, three, four, five, six, seven. The balance electron is seven. How many are there in this one? Seven. This has become their lowest symbol. It will say, I have seven. One of you can share yours. I will share mine too. You are stable, I am also stable. Right, so it already has seven. It will share one with this. Do you see the octet complete? Eight dots. He will say I have shared, you also do it, 7 is mine, 1 will be yours, so my octet will also be complete. This is equal sharing of electrons. When contribution is equal from both sides. If there was oxygen, then 2 electron pairs would have been shared, it would have become O2. If there was nitrogen, because it has 5, the other has also 5, 3 electron pairs would have been shared, and the molecule would have become N2. So whenever there is equal sharing of electron, what will be the bond? Covalent bond. If there is a single bond, it means there is one electron pair. If there is a double bond, it means there are two electron pairs. If there is a triple bond, it means there are three electron pairs. Are you getting this? Basic reason, how is a covalent bond made? A basic mechanism by overlapping of orbitals. Like an ionic is being made by transfer. How will this be made? overlapping of atomic orbitals. Is Char bond possible? Apart from that, normally Char bond Like single bond is being made, CL2, H2, HCL, H2O Double bond is being made, CO2, O2, there are many places Triple bond is also being made in many places Char bond is rarely made It is made in C2, that is conditional Delta bond is made, we will study further Similarly Char bond, why? Because there are only three axes. I told you that this is a directional bond. Overlapping will occur in a particular direction. So, it happened on x direction. It happened on y direction. It happened on z direction. Three bonds formed. Where is the fourth direction? Right? So, it is situational. We will study it later. But, overlapping is always directional. Overlapping will occur on a particular axis. Overlapping will occur on a particular coordinate. Is this clear to everyone? Okay? Single bond, double bond and? Triple bond. Let's read one important thing in this. Lewis structures. This is important. You should know how to draw this. Today's CPP is based on this. When did the Electrowell theory come? In 1916. Right? When was the introduction of this bond? In 1919. 3 years later, Louis of Cosell & Lewis Who worked with him? Langmuir He said that it is not necessary to have a transfer Only transfer can make a bond Sharing can also make a bond That's why Covalent Bond is also written in many books as Louis Langmuir concept So Louis told about the octet rule Yes, he said that there is another way to complete an octet. Sharing. From there, the introduction of covalent bond took place. Okay? The number of electrons that are being shared, like the number of electrons that are being transferred, that becomes electrovalency. The number of electrons that are being shared, that becomes covalency. Right? So, how much covalency is coming from this? One. How much is coming from this? It is sharing two electrons. Two. How much is coming from this? Three. The number of electrons shared is the covalency of that atom. Okay? Now, how will we make a Lewis structure? You can make any molecule, ion, what can you make? Lewis structure. In this, you will get to work with Lewis symbols. We will have to make dots, as many as the valence electrons. There are some steps to this. First, listen to the steps. Then, we will do the examples. Then, we will do the CPP. Then, your practice will be done. Right? How to make? First of all, You have to calculate the total number of valence electrons. Whatever species you have, whether it is a molecule or an ion, positive or negative, whatever, what you have to calculate is the total number of valence electrons. Suppose you are told CO2. So how will you calculate the total number of valence electrons in CO2? 6 plus 8 plus 8. In 2 oxygen atoms, 8 8. How many valence electrons are there in carbon? Sorry, 4. 4 plus? 6 plus 6. Total number of valence electrons. If there is any ion, suppose you have a positive ion, that is, a cation, then there is some positive charge on it. There is a negative ion, there is some negative charge on it. So when you calculate these valence electrons, if there is a positive ion, then minus the positive charge on it. Because that electron has already lost. If there is a negative ion, then minus the positive charge on it. add it. So suppose you are told carbonate ion CO3 2 minus. In this how will you calculate total number of electrons? 4 plus 6 into 3 plus 2. Because it has gained 2 electrons from somewhere. So how much will it be? 4 plus 6 into 3 plus 2. Suppose you are told ammonium ion NH4 plus. So how will the total number of valence electrons be? How many will be there? 5 Plus, in every hydrogen? 1 So 4 into 1 And it has lost one total electron So minus 1 So if there is a molecule Valence electrons will be added to total If there is a negative ion Then add the charge If there is a positive ion Then add the charge So from here, after this step You will get to know how many electrons are participating in the bond formation. How many valence electrons are there. Now, using your brain a little bit, you have to make a skeleton of that species. How to make a skeleton? Which atom will be in the center? Which atoms will be in the surrounding? In the center, there will be some central atom and around it, there will be other atoms. So, you have to decide the central atom. How will you decide? With your own brain. Then? Whose number will be less? Huh? Suppose, HClO4 is there. Suppose, I have given you this compound. Now, how will you decide which is the central atom in this? How will you decide which is the central atom? Can a hydrogen have a central atom? Because its valency is only... One more can make only one bond. Can a central atom ever be a fluorine? No. It has a valency of 1. It doesn't show any variable valency. So, a central atom cannot be a monovalent atom. So, this option is cut. Now, you have two options left. Oxygen and chlorine. So, which is less electronegative? That central atom will be. The one with the highest valency, which can make the highest bond, Only then it will be able to connect everyone. That will become the central atom. So, in any way, chlorine can expand its valency and it can reach up to 7 bonds. Oxygen can't expand its valency. Less electronegative is chlorine. Electronegativity of chlorine is 3. Oxygen's is 3.5. So, either see who is able to make more bonds, that will become the central atom. Or you can see which one is less electronegative. So, what you have to do in the next step is, you have to decide the central atom. And which is the central atom? The one whose valency is more or whose electronegativity is less. Which is less electronegative. Atoms like hydrogen and fluorine can never be central atoms. Did you understand this step? Now you have calculated the number of electrons and you have made a picture of who will be in the centre and who will be around. Now you have to distribute these electrons in all these. The basic principle of Lewis structure is the same. There are only Lewis structures. There is only one thing. The octet should be complete. If there is a small atom, then the duplet will be complete. If there is hydrogen, then the duplet will be complete. And if there is a big atom, then octet. He doesn't understand anything else. So all these electrons that you have calculated, they should be distributed between all the atoms that either their duplicate is complete or their octet is complete. Okay? If octet after making one bond, electrons are saved, then make multiple bond, double bond, triple bond. But what should be the octet and duplicate of all? Complete. Right, so what will you do in the fourth step? You will distribute the electrons. You will distribute electrons between all the atoms such that what is complete? Octet or duplet. Let's understand this with a simple example. The first step in CO2 is to calculate the total number of electrons. How many electrons are there? 4 plus 6 plus 6. How many electrons are there? 16. That means you have to distribute 16 electrons between carbon and oxygen. Now you have to decide the central atom. Who will it be? Carbon. Less electro, negative. So, carbon is kept in between. Oxygen can be kept anywhere. There is no constraint of shape in Lewis structure. That it has to be V-shaped or linear. Nothing like that. So, you kept one oxygen here. One oxygen kept here. What to do? Distribute these 16 electrons between them. Now, there will be one bond between all of them. At least one bond will be formed. One bond means two electrons. So, here two electrons, one bond is formed. Here two electrons, one bond is formed. How many are there out of sixteen? Four. Still the octet is incomplete. It is not done. One, two, three, four. Do more. Five, six, seven, eight. Eight out of sixteen are used. Now, can I make a third bond? Why? Because the carbon octet is complete. It is not oxygen, but the carbon octet is complete. I can't make a bond between these two. But I have the remaining electrons. I have used 8 out of 16. How many are left? 8. Now the remaining electrons, the oxygen, how will we complete their octet? They will be in the form of lone pair. Do you understand this point? So the bond that is formed is a bond pair. The one that is not formed is a lone pair. Now count it, total 16 electrons will be formed and all the atoms will have their octet completed. That means everything is stable and ultimately the molecule will also be stable. If we make a bond and its structure, how will it be formed? Double bond will form between carbon and oxygen and lone pair will form, two by two. Do you understand this? So calculate the number of valence electrons, decide the central atom, then distribute those electrons between those atoms. First of all, single bond will be formed between all atoms. Even then, if electrons are left, then make multiple bonds. Even then, if electrons are left, then if multiple bonds cannot be formed, then make lone pair. But the condition is only one, that octet or duplicate should be complete. Is it clear? Have you practiced CPP? Take it out. Let's discuss CO3 2-once so that you can also get iron. Try to make the Lewis structure of carbonate iron. CO3 2-Yes, carbonate iron. Try to draw its Lewis structure. CO3 2- Try, it will be wrong, what else will happen? Done? Copy me. The first step is to calculate electrons. How many are there? 4 plus 6 into 3 plus 2. Because it is a negative charge. How many are there? We have to distribute 24 electrons. Now, who will be the central atom of carbon and oxygen? Carbon. So, you wrote carbon. And how many oxygen do you have to apply? Three. So, one It will be a single bond between all of them. So make a single bond. That means you have distributed 1, 2, 3, 4, 5, 6 electrons. Carbon can make one more bond because its octet is not complete. So make one more bond in any of them. Anywhere. So here you have made one more bond. Now the octet of carbon is complete. No more bond can be made. Now what will happen? Lone pair. This oxygen has 4 electrons. Put it on the loam. 5, 6, 7, 8. Octet complete. It has just worked with 2 electrons. So 1, 2, 3, 4, 5, 6. It has the same condition. 1, 2, 3, 4, 5, 6. Count it. It has 24. Now this one and this one which is oxygen, they have made less bonds. How many bonds do we need to make? Two. But what is the amount of bond they have made? Less. What is the electron density on these? More. So, on this also minus charge will come and on this also minus charge will come. And what will this become? CO32 minus. Is this point coming in your mind? They had 6 electrons. How many electrons did they have to use? Two electrons. But they could only use one electron. Due to carbon. So what is the electron density on these? If it is more, then there will be a negative charge. Is everyone clear? Make ammonium ion. NH4+. NH4 plus ammonium ion. Done? Total electrons? 8. How many are there in this? 5 plus 4 minus 1. Because it is the charge of plus 1. How many total electrons do you have to distribute? 8. Who will be in the center? Hydrogen cannot be there. No option is left. Nitrogen has to be there. So, nitrogen in the middle. And you have to apply 4 hydrogen. You can apply it any way. It is not necessary. 1, 2, 3, 4. Apply it like this also. No problem. The actual structure will come forward. Okay. There will be a bond between all. So, we made one bond. How many electrons were used? 1, 2, 3, 4, 5, 6, 7, 8. How many electrons were to be distributed? 8. But this positive charge remained. On which? On nitrogen. Because nitrogen makes 3 bonds. It used its lone pair more than its capacity. What is the atomic number of nitrogen? 7. What is the configuration? 1 is 2. 2s2 2p 3 How many electrons does it have in the outermost? 5 Valency, calculate it normally 8-5, how many comes? 3 How many bonds does it make? 3 One lone pair remains on it But in this species, it has used its lone pair as well That's why it made the fourth bond That means, what happened to its electron density? Less That's why it will get a positive charge So, the positive charge in ammonium is coming on nitrogen. We will study this further. It has a co-ordinate bond. We will study this further. But, we are understanding the Lewis structure. The duplet of hydrogen is completed. The octet of nitrogen is completed. Clear? Now, take out CPP. Do the first question. Sulphate iron. Make sulphate iron. Have you got CPP? Do it. What is the valency of sulphur? 8 Sulfur belongs to the oxygen family only, right? So, the amount of valence electrons in oxygen, will be in sulphur only. 6 Don't forget the periodic table. It will be with you all your life. Dear, it will be with you all your life. How can you not take it? You have to take it. Now you will say, ma'am, we will do job or business, so how will our periodic table work in that? But you will grow further. Will you get married? Even if you don't, it's okay. You will have kids. Will you teach them chemistry? You will make them learn too. You will make them learn. Periodic table will work together. Make it. SO 4 2-No one could make it. I am calling you now to make you on board. Tell the truth. I do very few questions. I have heard that you have more questions than me in other classes. It doesn't happen. You are lying. Mr. Yogesh does a lot of questions. Doesn't he? He does, right? No problem. Okay, like this? Like this? Okay. Anyone? So, the next statement is that you also don't apply it. This is the next statement. You also don't apply it. He has never applied it, you also don't apply it. Okay, SO4-2. Tell me honestly, who didn't make it? It didn't shine at all, what is to happen? There is nothing to be ashamed of, nothing to be hesitated about. If it is not being made, then it is not being made. It is not being made. I don't understand at all. But it is not being made. Any more? What about the rest? What is the first step to be done? Number of electrons calculate. Step is same. So, in sulfur and oxygen, it is equal. Six Pfizer is 30. Plus two. How many are there? 32. You have to distribute 32 electrons in it. You must have taken it wrong. Sulfur and oxygen belong to the same family. Both have 6 valence electrons. Minus, yes. You have to do plus 2. Now who will be in the center? Sulfur. Distribute 4 oxygens around it as you want to write. Single bond will definitely be made. Make it. Now, is the sulfur coctet complete? No, it's not? It's done, right? The other remaining electrons? What? What will you make? Will it be made? You tell me. Tell me. Loan pair, double bond, Lewis structure. Lewis structure. Where will it be made? Where is the scope? 1, 2, 3, 4, 5, 6, 7, 8. 8 Sulfur Octade is completed. Now, Let me apply Lone pair of Oxygen. Let me apply Lone pair of Oxygen. How many should I apply? 6-6. Let's apply. How many are there? Charge. A linear structure will be formed. How linear? Yes. Sulphur and oxygen. This side. Both sides. Okay. Then? One more oxygen on this side. Now what should I do? Should I make a bond between them? How many? Single. Then? Should I make a double here? No, it won't be like this. You made it, right? You all told me the answer, right? You were telling the answer, B. How did you get B? You told me the answer, B. How did you get B? Number of loan pair and bond pair in SO2. SO4, 2 minus. Huh? If we make a bond pair of 4, then the bond pair is 4. 1, 2, 3, 4. And how much is the loan pair? 12. So, how much is the answer? 12 and 4. But where is 2 minus? Sulphur will be applied. 2 minus. Sulph is there. In other structure, oxygen is applied. It looks like this. Actually, it is there. Because what can sulphur do to its valency? Expand. Right? By the way, how much is the normal valency like oxygen? 2 How much is the normal valency like oxygen? 2 So how many bonds should sulfur actually make? 2 But in that 3D So it can expand its valency So what does it do with 2 electrons, 2 oxygens? It makes a double bond And each single single one gets charged on them This is the actual structure This is actual. But keep in mind that you are asked this question. For example, let's talk about this. He asks how many sigma bonds and how many pi bonds are there in the Lewis structure. This is SO. Or just talk about SO. Understand this question very carefully. This question has come up many times. How many sigma and how many pi bonds are there in the Lewis structure of SO? How do we make SO? Like this. Because sulphur can expand its balance, it can go up to 6 bonds. Plus 6 is the oxidation state of it. Now accordingly, 1 sigma, i.e. 3 sigma and 1 pi. How many are there? 3 pi. And this is done in the option. But in the question, it is written in its Lewis structure. In its Lewis structure. So in the Lewis structure, more than 8 electrons. No, it won't. Lewis structure and how will it be made? Like this. On this, it came minus, on this it came 2 plus, overall neutral. I will tell you the same thing in that experiment. On this, it came minus and on this it came, it made two more bonds. It made two more bonds, so on this it came 2 plus. They have made one less bond, so on this it came minus minus. Overall it became neutral. Is this point clear? Now tell me how much is sigma and how much is pi? 3 sigma and 1 pi. This is the correct answer. Because in the question it is written in the Lewis structure of SO. If it is written only in SO, then it would be different. It is written in the Lewis structure of SO. So this answer will come. It will be in both the options. Now we will do the same thing here. Sulfur has to make two bonds, usually, but it has made four. It has made two more, but its electron density has decreased. How much has decreased? This much has decreased. And all of them have made one less bond. All of them have made one less bond. So, minus, minus, minus, minus. Now, tell me, how much is the total? Minus two. Now, do you understand how minus two has come? Sulfur has made more than its capacity. So the charge is positive. Oxygen is made less than its capacity. So negative charge is minus 4 plus 2. What will be the total? Minus 2. But if bond pair and lone pair will ask, then count and tell. If sigma-bi will ask, then see and tell what is single bonded and double bonded. Are you understanding the question? So if the Lewis structure is written in the question, then answer accordingly. Huh? Son, the usual normal valency of sulphur is 2, right? What is the configuration of sulphur? 2, 8, 6. What is its valency? How many bonds does it make? Covalent bonds have covalency of 2, right? Covalent bonds have to make it 2. But because it had 6 electrons in valence, 4 electrons were there which it could use, but usually, it doesn't. What did it do in this? In some... So, we used all of them. So, the capacity was 2 but how many bonds did we make? 4. So, we made more than 2 bonds with our capacity. On this, the electron density will decrease. See, there is no lone pair of this. If there was a lone pair, then the charge density would have been more. If there is no lone pair, then the charge density has decreased. So, the charge has come positive. How much positive? The more extra bonds we made. If we made 2 extra, then it is 2+. Oxygen had to be used but it didn't. If it's not used, then the charge density is higher, so the charge is minus. Is this concept clear to everyone? Now what do you have to do after going home? You have to do your CPP and bring it in the next class.

We can take melting points, melting and boiling points. Melting and boiling points. How will they be? High. Right?

Why? Because these two depend on force of attraction. Where force of attraction will be more, what are melting and boiling points? High.

And in ionic compounds, there are opposite ions, so definitely force of attraction will be very strong. So how will the melting and boiling points be? They will be high. Okay.

Next comes electrical conductivity. Electrical conductivity. Hmm? Huh?

Electrical conductivity is negligible. Electrical conductivity is negligible for ionic compounds. When they dissolve in water, they conduct. That's it. They conduct in a molten state.

Will any ionic compound conduct in a solid state? Electricity? Prince?

Where were you lost? What were you thinking? The question I asked, were you thinking?

Did you think? Answer me. In a solid state, no ionic compound will conduct electricity?

Sit. Sit. Look, in a solid state, an electrical conductor will not be there. Why? Because conduct...

To conduct electric current, it is important to have a charge move. Right? Rate of movement of charge. If there is an electron but it is not able to move, then there will be no conductivity.

If there is an ion but it is not able to move, then there will be no conductivity. So when we talk about solid state, then what will remain in an ionic compound in a solid state? It is a very strong force of attraction. So ions will hold each other so strongly that they will not let each other move. And there will be no conductivity.

But if you have... Convert to what? Molten state. Molten state means you have heated it and melted it.

What will happen by melting? Force of attraction will become weak. Ions will become distant.

Now it will be able to move and the compound or substance will show conductivity. So either convert it to molten state or convert it to its aqueous solution. Aqueous solution means you have put it in water. Even after pouring it in water, what happens to ions?

Separate. It will become a solution. Then, if you put an electrode and complete the circuit, then the current will flow. So, in the molten state or aqua solution, any ionic compound will be a good conductor of electricity.

In the solid state, it will not conduct electricity. If it is in the pure state. But if there is any impurity in it, All the dropper children, remember the solid state a little bit. We read defects.

So if there is an impurity in its crystal, if another foreign atom comes, then it may be due to that that conductivity shows. But if we talk about general condition, then that conductivity will not show in solid state. Conductivity will show in the form of molten and aqueous solution.

Conductivity will show in the form of molten and aqueous solution. Is this clear? Are you writing along?

It is not looking. You have to remind yourself every time that you should write. Write it together.

Or you become a mantra-free by looking at me. That you forget. You just keep looking at me like this.

Okay. Fifth. Fifth property is solubility. Solubility. Think and tell me.

In which type of solvent are ionic compounds dissolved? In which type? In polar. For example, the most common polar solvent is water.

And in non-polar? Are they dissolved in non-polar? No, they are not. First of all, think about whether you understand the term polar or non-polar. Because we have already studied it.

I have taught you polar and non-polar in periodic table. Twice. So, is the picture working in your mind as soon as you hear the word polar?

Polar means, there are two poles, electric poles, one positive and one negative. So, wherever there is charge separation, whether it is partial or complete charge separation, it is called polar. Two poles are formed, one positive and one negative, the charges are separated.

And where there is no charge separation, it will become non-polar. So, the solvents in which we dissolve things, we have divided them into two categories, polar and non-polar. Polar solvent is the one which has charge separation. Non-polar is the one which does not have charge separation.

Now, on what does charge separation depend? It depends on their difference in electronegativity. Do you remember that example of pulling a rope? Electronegativity.

If someone has a lot of electronegativity, then he will pull the electron towards himself. That side will become negative and the other side will become positive. If both have the same electronegativity or almost the same, then the electron will not go anywhere. In that case, how will the molecule be?

Non-polar. You have studied it, right? Yes? So, what is there in these ionic compounds? Are the charges separate or not?

Is there a charge separation in ionic compounds or not? There is one positive and one negative. Negative is like you took NaCl, so NaCl has Na plus and Cl minus. In this charges are separate, complete separation is there. So in chemistry there is an aphorism, there is a saying in chemistry, it is said like dissolves like.

Have you heard in childhood, like dissolves like. Like dissolves like means, whatever is there, it will dissolve in that. So if it has charge separation, i.e. it has a polar nature, then in which type of solvent will it dissolve?

The one which is also polar. Like dissolves like. And what will remain in non-polar? Insoluble. Are you understanding this basic concept?

Yes? So because in ionic compound there is charge separation, in which will it dissolve? They get dissolved or they are soluble in polar solvents.

They are soluble in Polar Solvents The best example of Polar Solvents is water I have explained to you many times that what is in water? It is this condition There is a huge difference between Oxygen and Hydrogen in Electronegativity So, due to this, Oxygen becomes negative and Hydrogen becomes positive This becomes Polar Now, imagine this whole thing You have put NaCl in water There is water all around So, what will happen? Water. This is?

Who will come near this? The end of oxygen. Who will come near this?

The hydrogen one. I have already explained it. So who is surrounding this?

Water from the side of oxygen. Water is coming from the side of oxygen. And who is coming near CL minus?

The side of hydrogen. It is interactive. interacting with water.

What is it doing with water? It is interacting with water. Now the force of attraction between them, will be more than this force of attraction.

Me and Himani have held hands, we both have force of attraction. Now many people are pulling me from behind, many people are pulling him from behind. This is the situation.

So our force of attraction will come to a point and break. Because this surrounding force of attraction, what will it do? It will overpower, it will overcome.

As soon as this happens, their force of attraction breaks and these two will be different. As soon as they are different, that compound will be dissolved in water. Is this point coming to your understanding? Okay. This capacity, this tendency of any solvent to separate the charges.

The capacity of a solvent, the tendency of a solvent to separate the charges is called The capacity of any solvent, someone can do this very well to separate the charges and someone can do it a little less, someone can do it a little less, someone can do it a little less, but they can't do it at all. Everyone's solvent nature is different, right? So, the capacity of any solvent to separate the charges, to dissolve things in itself, what is this property? Hydration is a process.

This process is known as hydration. To interact with water is hydration. Addition of water is hydration.

We say we are feeling dehydrated. There is a lack of water. The other person says drink water and you will be hydrated. Hydration.

Taking in water, contact with water, interaction with water. That's the process. Any solvent's capacity to separate the charges is its dielectric constant.

Dielectric constant. Have you ever heard this term? Have you heard? Dielectric constant. What is dielectric constant?

The tendency of a solvent to separate the charges. Whose dielectric... The more the dielectric constant, the more it can easily separate the charges and things can dissolve better. Water's dielectric constant is very high, 82. That's why maximum things get dissolved in water. We say water is the universal solvent.

Because it dissolves maximum things. Are you getting the point? Yes? So write dielectric constant for those who don't know.

Dielectric constant is what? It is the tendency of a solvent to separate charges. The capacity to separate charges of any solvent is its dielectric constant. Now, let's combine these two points.

The ionic compound will be dissolved in a solvent which is polar and whose dielectric constant is high. You understand this process, there are two things happening in this. First, these two are getting attracted. Why? Because there is a charge in this and there is a charge in this.

That means both are polar. Because both are polar, what will they do at the opposite ends? They will get attracted.

then it will be engulfed by water. If it is not polar, then there will be no interaction between these two. Then the second step will be that their attraction will increase so much that they will separate.

This is the point. Are you understanding this point? There are two processes.

First, it is engulfing with water and interacting with it. And then water is pulling it so much because its dielectric constant is high. What is it doing to both the ions?

Separate. then that compound dissolves in water. Are you getting this point? Yes?

So what will we say? Ionic compounds are soluble in those solvents which are polar and which have high dielectric constant. Like water. Is this point coming to your mind? If there is an organic solvent whose dielectric constant is moderate, then also the ionic compound will dissolve.

Like methyl alcohol. CH3OH, its dielectric constant is around 32. So some of the ionic compounds get dissolved in it. But if you have ether, you have benzene, you have CCL4, which is completely non-polar, then ionic compounds won't get dissolved in it.

So a solvent which has polarity and whose dielectric constant is high, the ionic compound will get dissolved in it. Do you understand this point? This process, interaction with water, is called hydration.

Interaction of a compound with water is called hydration. Now think and tell me, will energy be required or released in this process? Will energy be required or released in this hydration process?

Will it be required? Because the force of repulsion is more than the attraction. I have explained you the basic concept.

Where the attraction is more, the energy will be released. Where the repulsion is more, the energy will be required. Now think and tell me.

Is the attraction going on here or is the repulsion running far or is it coming near? Then energy will be released. There is a... force of attraction between water and that ionic compound, isn't it?

This attraction is not visible. O minus minus minus Na plus. H plus plus plus plus Cl minus. Attraction is happening, isn't it?

And this force of attraction is increasing. That's why that compound is dissolving. Otherwise, it doesn't break. Yes, so energy will be released in this. And every energy has a name.

What will be its name? Hydration Enthalpy Hydration Energy So the process is Hydration And the amount of energy That is being released in this Will be the Hydration Enthalpy Some will have less Some will have more Now the solubility of that compound will depend on this hydration enthalpy. It will depend on lattice enthalpy as well as on hydration enthalpy.

So write it down. This process of interaction of water and ionic compound is known as hydration. And the amount of energy released is called hydration enthalpy.

The amount of energy released during hydration is called hydration. Enthalpy. Who's class is after my class? In your batch?

It's everyday. Okay, after my class, it's always physics. So physics happens in the morning and then repeats. Is there any doubt at any point?

Hydration enthalpy is the amount of energy released during hydration of a compound. Amount of energy released during hydration of a compound. Write it with your head up.

Everyone's eyes will get damaged. If you're having fun. Yes. Your eyesight will get weak. Keep your head up a little.

Clear till here? Next property, which type of reactions will ionic compounds show? Obviously ionic reactions.

One is the reaction in which atoms and molecules participate, another is the reaction in which ions participate. So of course, which will be the reactions of ionic compounds? Ionic reactions in which ions participate.

For example, you took NaCl's Aqua solution and mixed it with AgNO3's Aqua solution. Have you ever read this reaction? You made Aqua solution in two test tubes and then mixed it.

So, as soon as you make Aqua solution, will this process work? And in which one will it be broken? In Na plus and Cl minus.

This will also be broken in Ag plus and... NO3 minus. Now, in which reaction is it happening?

It is happening in ions. There are no atoms and molecules. So, what type of reaction will this be? Ionic reaction. And ionic reactions are very fast reactions.

As soon as you mix these two, AGCL's white PPT will be formed. As soon as you mix it, it won't take long at all. Whereas, if there are atoms and molecules in the reaction, i.e. if there is a molecular reaction or a covalent reaction, then it takes some time. Because first, their bonds break.

Then new bonds are formed. There is no such problem in this. Bond breaking happened in the first aqua solution itself. Their bonds have been broken in their own aqua solution.

Now, it is just bond formation. As soon as they mix, they will attract. As soon as they attract, they will form a compound. So, the ionic compounds show ionic reactions which are very fast.

Those which have very fast reactions. Have you ever read the term isomers or isomerism? Do you remember what isomerism is?

You have heard of it but you don't remember. Why don't you guys recall what you read? You didn't have to spend a lot of time reading it.

It's been a long time since you were studying, right? Why can't you recall? This problem is with everyone.

You can't recall. Why can't you recall? You are studying, you are working hard, but still you can't recall. This is heart-wrenching. You are studying, but at the time you should remember, when it is needed, you are not remembering.

Iso-mers. Many things are self-explanatory. You don't pay attention. You are just reading, but you are not reading mindfully.

Every name explains itself. Your name must have some meaning, right? Like my name means Punam. Punam ka jaan. It means, right?

Isomers. Isotopes, isobars, isotones, isoelectronic species. Iso-diafers, isosters, isomorphs, isomers, iso, iso, iso, iso, iso, iso means?

Something or the other. Mers, monomer, polymer, monomer, dimer, trimmer, mer, mer, mer, mer. Dimer, dimer means? Two molecules, two units.

Trimer, three units. Monomer? Polymer. So what does mer mean?

Molecules, units. Iso means same, mer means units. Such compounds whose molecules are same. Such compounds whose molecular formula is same. But somewhere or the other, some property will be different, so there will be different compounds.

Relate things like this. Study them mindfully. Or make some writing trick.

Or if you know the meaning of it, then you will remember it. So isomer means compounds whose molecular formula is the same but some property varies between them. That's why they are different compounds. Now when we talk about ionic compounds, they don't show isomerism.

Ionic compounds don't show isomerism. You will understand this better when you study isomerism in organic. If you study Stereo-Isomerism and Structural then you will understand better.

Now the most important point that I want to explain to you is that Isomerism does not show and why it doesn't show? Very very important because there is no direction of the ionic compound. There is no direction of ionic bond.

Ionic bond is non-directional. You have to take some basics along with you, otherwise it will be very difficult for me to explain everything. You guys are so blank that I have to start everything from zero. I think bond is non-directional.

What does this mean? Any direction of it, like covalent bond. What is there in covalent bond? Overlapping.

What is there in covalent bond? Overlapping. S-S, S-P, P-P, P-D, there is overlapping. Overlapping means two things are overlapping each other. This will always be in direction.

X direction, Y direction, Z direction. Overlapping will occur on an axis. It will be on a coordinate.

It will be in X direction, Y direction, Z direction, X and Y direction. So, there will be a direction of covalent bond. Ionic bond has an ion. How is its electric field?

It is uniform. It is not on the X axis or Y axis. So it has a uniform electric field. What did it do because of uniform electric field? It attracted opposite ions from all sides.

Is there any direction? No. When there is no direction, if you lift the CL-here and do it from here, then there will be no difference.

Are you getting this point? So, Ionic compounds don't show isomerism. Why?

Because there is no direction of the bond. There is a difference in covariance. Because there is a direction.

If you put someone from here to there, there will be a difference. Are you getting this point? Yes? So, what will you write in the next property?

They do not show, Ionic compounds do not show isomerism. Ionic compounds do not show isomerism. Why?

Because ionic bond is non-directional. Ayanic bond is non-directional. Ayanic bond is non-directional. Tell me the truth, how many kids watch mobile phones before going to bed?

Tell me the truth, be honest. I am not going to buy your mobile phone. How many kids watch mobile phones before going to bed? This is one of the reasons why your recalling power is low.

There is a technique called 321. The 321 technique is used to increase your memory. and recalling power. Both of them have to be increased. So, you apply this technique. What is this technique?

Three hours before sleeping. Three. Three hours before.

Anything. That means, the food you want to eat is to be eaten three hours before. After that, you don't want to eat. Three.

Two. Two hours before sleeping. Two hours before sleeping.

What do you have to do? Any relaxing, meditation, anything. Close your eyes and sit. Bring some positive thoughts. And one hour before sleeping, keep all your gadgets away.

Whether it's a laptop, phone or TV. After that, one hour after that, you sleep. This will work magically. Keep all your gadgets away one hour before. What do you do?

You keep them away one minute before. After looking at the phone, Facebook, Instagram, YouTube, Reels. And then, now I will get a good sleep. Sleep will be good. But it will go in the brain.

So, your memory and recalling will go down. Over the period of time. What? Should I tell you again? Eat food 3 hours before going to sleep and then don't eat anything.

Digestion is for you. You are a child of bio, you understand the process of digestion. What to do 2 hours before?

Some positive thoughts. Talk to your parents. You can get positivity from anywhere.

Right? Like I said one day, listen to instrumental music. Or talk to your parents. If they know meditation, then do some meditation. And 1 hour before, turn off all gadgets.

Screen off. Then sleep. These are not my mind-blowing stories that I tell you. All this is scientifically proven. Yes, you can watch gadgets an hour before.

Close it. Sleep after an hour. So if you want to sleep at 11, then close your phone at 10. TV, phone, laptop, PC, VC.

Close everything. Okay? Yes.

Video lecture, first watch it, then read it from the book. It is not necessary to watch video lecture before sleeping. It is not necessary.

If you watch video lecture during the day, then if you want to practice something, then do that. Do it from the book, read it from the notes. Okay, so these were the properties of ionic compounds. Now, let's discuss a small topic which is important also.

Variable Electrovalency. Variable Electrovalency. This is important.

Variable electrovalency. Do you remember electrovalency? The valency in the ionic compound will become electrovalency. Variable means which is not fixed. Which changes.

Like you must have read iron. Iron compound FECL2 and FECL3 is also formed. FEO is also formed. FECL2 is also formed.

So if we talk about valency in this, So, if we talk about the oxidations, then how much is going on in this? Plus 2, how much is going on in this? Plus 3. Another common example is copper. What does copper show?

It also shows the valency of plus 1 and plus 2. This is more stable in both. And maybe you have heard of tin. Tin also shows plus 2 and plus 4. Lead is present.

Lead also shows plus 2 and plus 4. Thallium is there. Thallium also shows 1 and 3. Right? Bismuth is there.

Bismuth also shows 3 and 5. So, a lot of metals, especially those of D block, especially DK, PK, all of these show wearable valency. They have wearable electrovalency. Okay? What are the reasons? If we discuss about iron, what are the reasons?

Electronic configuration, very good. What is the electronic configuration of Fe? Fe is 3d6 4s2.

26 atomic number. What is the configuration? 3d6 4s2.

What is valency? You must have studied in your childhood, you get valency on the basis of the electrons in the outermost shell. So how many electrons are there in its outermost shell?

Two. If in the outermost shell, we have read in periodic also, if there are 1, 2 or 3 electrons in the outermost shell, then that is its valency. How many 2 are there in its outermost shell? So its valency is also 2, justified.

But what is it showing along with 2? It is also showing 3. Why? Because if it loses one more electron from here, then its configuration will be 3D5 and it will be half-filled and hence more stable. Top!

By formula, by default, plus 2 will show. It will definitely show. But what does it show along with it?

Plus 3. And what is its configuration in plus 3? 3D 5, which is more stable. That's why its compounds in plus 3 are more stable. Tell me about copper.

What is the configuration of copper atom? 3D 10 4S 1. This is copper, right? So, there is one electron in the outermost. Valency 1 can come. Justified.

Why this? When after losing one electron, it is fulfilled. If it loses one electron, it will show the valency of plus 1. So, it is fulfilled. And fulfilled means stable.

So, why it loses one more electron and makes it plus 2? It is more stable than plus 2 plus 1. It is more stable than plus 2 plus 1. Whereas in this, its configuration is 3D10 In this, its configuration is 3D9 If you apply the concept of electronic configuration, then it should be stable It should not be made But this is more stable Why? What? What is the reason for this?

Yes Yes, very good Where is all this being made? It is being made in the Aqua solution Where will the ion be made? It will be formed in the Aqua solution. What is working in the Aqua solution?

Hydration. What energy is working? Hydration, Enthalpy.

Now understand this. Its size has become small. The more the positive charge increases, the smaller the size of the ion.

So what has become its size? Small. Its charge has become more magnitude wise.

Plus 1, plus 2. So the charge has increased and the size has become small. So overall charge density has increased. As the charge density increases, its electric field becomes stronger. It interacts with water more.

Hydration enthalpy increases. And the more energy is released, the more stability the system gets. Do you understand this point?

So although it is less stable in configuration, but it has high hydration enthalpy. And that's why What will be more stable than the state of plus 2 plus 1? Clear? Tell me about all these. All these are of the same type.

All these have the same reason. See, how much difference is there between these? See, in these...

3. Who said 3? In these... In all these, the oxidation state is differing from 2 to 2. Right? The reason here seems to be...

That is called inert pair effect. The reason here is inert pair effect. Important. Okay.

Now, which family does tin belong to? Which family does tin belong to? Carbon. Under carbon, nitrogen.

Nitrogen comes like this. Carbon, silicon, germanium, tin, lead, and flavorium. Right?

So, carbon, silicon, germanium, tin, and lead. They are coming in the same family. Where is this coming from?

Boron family. Right? Boron. Aluminium, Gallium, Indium, Thallium.

This is Thallium. This is Nitrogen family. Nitrogen, Phosphorus, Arsenic, Antimony, Bismuth. You see one thing common in all of them. These are lower elements.

These are not the upper elements, these are the lower elements. The lower elements means they are heavy. The lower mass is more, right?

These are heavy elements. And which group are they from? Group 13. 14, 15. We are in P block.

Group 13, 14, 15. And below, 6th period, 7th period. Now, remember the table. Group 13, 14, 15. 6th period, 7th period. Who is coming before them? D and F.

Right? Before them... When this is filled, when Indium Thallium is filled, then Lanthanides Actonides will be filled and then this will be filled. Same for this, same for this. So before this, D and F are filled.

That means transition series is filled, Lanthanides Actonides are filled. And whenever inorganic is talked about Lanthanides Actonides, one common reason will be Lanthanide contraction, poor shielding effect. All the reasons revolve around this. So, how is the screening of D and F electrons?

Poor. How is the shielding effect of D and F electrons? Poor.

So, the D and F electrons which are before this, are not able to shield the nuclear charge, so the nuclear force of attraction on them must have increased. Z-effective, remember. What will be Z-effective for them? More.

Now see, what is the configuration of the carbon family? Tell me. Carbon family's configuration is outermost. NS2NP2 Right? Before this, what is the boron family?

NS2NP1 What is the nitrogen family? NS2NP3 Right? Where N is the balance shell. Now, how many electrons are there in its balance shell? 3 That's why valency 3 is also coming.

How many electrons are there in its valence shell? 4 So, valency 4 is also coming. How many electrons are there in its valence shell?

5 So, valency 5 is also coming. This is what should come in the normal configuration. But, because Z-effective has increased, because nuclear force of attraction has increased, so it must have increased so much that these electrons with S will become inert.

Because it is being attracted by the nucleus. And this is always a pair of electrons. That pair of electrons is becoming inert. So what is the name? Inert pair effect.

Inert means that it will not be able to participate in the bond formation. When it will not be able to participate, then its valency is 1, 2, 3. So, their valency will be less than 2 units because these NS2 electrons are not participating. Did you understand this effect?

Sure. Let me repeat it once. Where will this group 13-14 be? Now write the small points. Inert pair effect.

Where will it show? It decreases a little in group 15 but it shows very well in group 13-14. So, it will be applied in group 13-14-15.

And in 13, 14, 15, heavier elements will be applied. So inert pair effect is applicable to heavier elements of group 13, 14, 15. Inert pair effect is applicable to heavier elements of group 13, 14, 15. Okay? And what is happening? Due to poor shielding effect of D and F electrons, due to poor shielding effect of D and F electrons, Z effective on these elements increases.

Due to poor shielding effect of D and F electrons, Z effective on these elements increases due to which due to which the ns pair of electron due to which the ns pair of electrons the ns pair of electrons become inert. Hence their electrovalency decreases by 2 units. Hence, their electrovalency decreases by 2 units.

Did you understand? So, boron family plus 1 plus 3. This will show carbon family plus 2 plus 4. And nitrogen family plus 3 plus 5. Which one will be more stable? Suppose you are asked to decide. Is lower more stable or higher more stable?

Lower. Lower is more stable. If the compound of tin is SNCl2 and SNCl4, which one is more stable? This one. So, the lower valency will be more stable.

Is it clear? Has everyone got CPP? Not today? Okay, but today, what will happen? There will be Lewis structures.

Okay, so what has been completed here? Ionic bond. How was Ionic bond made? By transfer of electron.

What was the second method of making a bond? There were three methods. One method was complete transfer. Second method was equal sharing. Third method was unequal sharing.

So we completed the first method. Bond was made, compound was made, property was studied. Now the second method is equal sharing of electron. Maximum questions will come from here. Covalent bond.

Covalent. Co means together. Coordinate. Co-operate. Similarly, covalent.

Valent, valency. Bond formation. They are helping each other by equal sharing of electrons. So how is covalent bond made? Covalent bond is formed by equal sharing of electrons.

Now when will it be made? When will this happen? Suppose there are non-metals and non-metals. Right? One is Cl and the other is Cl.

What is the tendency of both of them to gain electrons? Non-metals are electronegative. There is no donor. There is no one to give. So they don't have the option of taking.

But they have to be stable. They are unstable. So what will they do for that? They will share their electrons equally. If we make the lowest symbol, how will it be?

How many dots should I put? Seven. One, two, three, four, five, six, seven.

The balance electron is seven. How many are there in this one? Seven. This has become their lowest symbol. It will say, I have seven.

One of you can share yours. I will share mine too. You are stable, I am also stable. Right, so it already has seven.

It will share one with this. Do you see the octet complete? Eight dots. He will say I have shared, you also do it, 7 is mine, 1 will be yours, so my octet will also be complete.

This is equal sharing of electrons. When contribution is equal from both sides. If there was oxygen, then 2 electron pairs would have been shared, it would have become O2. If there was nitrogen, because it has 5, the other has also 5, 3 electron pairs would have been shared, and the molecule would have become N2.

So whenever there is equal sharing of electron, what will be the bond? Covalent bond. If there is a single bond, it means there is one electron pair. If there is a double bond, it means there are two electron pairs.

If there is a triple bond, it means there are three electron pairs. Are you getting this? Basic reason, how is a covalent bond made? A basic mechanism by overlapping of orbitals.

Like an ionic is being made by transfer. How will this be made? overlapping of atomic orbitals. Is Char bond possible?

Apart from that, normally Char bond Like single bond is being made, CL2, H2, HCL, H2O Double bond is being made, CO2, O2, there are many places Triple bond is also being made in many places Char bond is rarely made It is made in C2, that is conditional Delta bond is made, we will study further Similarly Char bond, why? Because there are only three axes. I told you that this is a directional bond.

Overlapping will occur in a particular direction. So, it happened on x direction. It happened on y direction. It happened on z direction. Three bonds formed.

Where is the fourth direction? Right? So, it is situational. We will study it later.

But, overlapping is always directional. Overlapping will occur on a particular axis. Overlapping will occur on a particular coordinate.

Is this clear to everyone? Okay? Single bond, double bond and? Triple bond. Let's read one important thing in this.

Lewis structures. This is important. You should know how to draw this.

Today's CPP is based on this. When did the Electrowell theory come? In 1916. Right?

When was the introduction of this bond? In 1919. 3 years later, Louis of Cosell & Lewis Who worked with him? Langmuir He said that it is not necessary to have a transfer Only transfer can make a bond Sharing can also make a bond That's why Covalent Bond is also written in many books as Louis Langmuir concept So Louis told about the octet rule Yes, he said that there is another way to complete an octet. Sharing. From there, the introduction of covalent bond took place.

Okay? The number of electrons that are being shared, like the number of electrons that are being transferred, that becomes electrovalency. The number of electrons that are being shared, that becomes covalency.

Right? So, how much covalency is coming from this? One. How much is coming from this?

It is sharing two electrons. Two. How much is coming from this? Three.

The number of electrons shared is the covalency of that atom. Okay? Now, how will we make a Lewis structure?

You can make any molecule, ion, what can you make? Lewis structure. In this, you will get to work with Lewis symbols. We will have to make dots, as many as the valence electrons. There are some steps to this.

First, listen to the steps. Then, we will do the examples. Then, we will do the CPP. Then, your practice will be done. Right?

How to make? First of all, You have to calculate the total number of valence electrons. Whatever species you have, whether it is a molecule or an ion, positive or negative, whatever, what you have to calculate is the total number of valence electrons.

Suppose you are told CO2. So how will you calculate the total number of valence electrons in CO2? 6 plus 8 plus 8. In 2 oxygen atoms, 8 8. How many valence electrons are there in carbon?

Sorry, 4. 4 plus? 6 plus 6. Total number of valence electrons. If there is any ion, suppose you have a positive ion, that is, a cation, then there is some positive charge on it. There is a negative ion, there is some negative charge on it.

So when you calculate these valence electrons, if there is a positive ion, then minus the positive charge on it. Because that electron has already lost. If there is a negative ion, then minus the positive charge on it.

add it. So suppose you are told carbonate ion CO3 2 minus. In this how will you calculate total number of electrons?

4 plus 6 into 3 plus 2. Because it has gained 2 electrons from somewhere. So how much will it be? 4 plus 6 into 3 plus 2. Suppose you are told ammonium ion NH4 plus. So how will the total number of valence electrons be?

How many will be there? 5 Plus, in every hydrogen? 1 So 4 into 1 And it has lost one total electron So minus 1 So if there is a molecule Valence electrons will be added to total If there is a negative ion Then add the charge If there is a positive ion Then add the charge So from here, after this step You will get to know how many electrons are participating in the bond formation.

How many valence electrons are there. Now, using your brain a little bit, you have to make a skeleton of that species. How to make a skeleton?

Which atom will be in the center? Which atoms will be in the surrounding? In the center, there will be some central atom and around it, there will be other atoms.

So, you have to decide the central atom. How will you decide? With your own brain.

Then? Whose number will be less? Huh?

Suppose, HClO4 is there. Suppose, I have given you this compound. Now, how will you decide which is the central atom in this?

How will you decide which is the central atom? Can a hydrogen have a central atom? Because its valency is only... One more can make only one bond. Can a central atom ever be a fluorine?

No. It has a valency of 1. It doesn't show any variable valency. So, a central atom cannot be a monovalent atom.

So, this option is cut. Now, you have two options left. Oxygen and chlorine.

So, which is less electronegative? That central atom will be. The one with the highest valency, which can make the highest bond, Only then it will be able to connect everyone. That will become the central atom.

So, in any way, chlorine can expand its valency and it can reach up to 7 bonds. Oxygen can't expand its valency. Less electronegative is chlorine.

Electronegativity of chlorine is 3. Oxygen's is 3.5. So, either see who is able to make more bonds, that will become the central atom. Or you can see which one is less electronegative.

So, what you have to do in the next step is, you have to decide the central atom. And which is the central atom? The one whose valency is more or whose electronegativity is less.

Which is less electronegative. Atoms like hydrogen and fluorine can never be central atoms. Did you understand this step?

Now you have calculated the number of electrons and you have made a picture of who will be in the centre and who will be around. Now you have to distribute these electrons in all these. The basic principle of Lewis structure is the same. There are only Lewis structures.

There is only one thing. The octet should be complete. If there is a small atom, then the duplet will be complete.

If there is hydrogen, then the duplet will be complete. And if there is a big atom, then octet. He doesn't understand anything else.

So all these electrons that you have calculated, they should be distributed between all the atoms that either their duplicate is complete or their octet is complete. Okay? If octet after making one bond, electrons are saved, then make multiple bond, double bond, triple bond.

But what should be the octet and duplicate of all? Complete. Right, so what will you do in the fourth step? You will distribute the electrons.

You will distribute electrons between all the atoms such that what is complete? Octet or duplet. Let's understand this with a simple example.

The first step in CO2 is to calculate the total number of electrons. How many electrons are there? 4 plus 6 plus 6. How many electrons are there? 16. That means you have to distribute 16 electrons between carbon and oxygen.

Now you have to decide the central atom. Who will it be? Carbon.

Less electro, negative. So, carbon is kept in between. Oxygen can be kept anywhere.

There is no constraint of shape in Lewis structure. That it has to be V-shaped or linear. Nothing like that.

So, you kept one oxygen here. One oxygen kept here. What to do?

Distribute these 16 electrons between them. Now, there will be one bond between all of them. At least one bond will be formed.

One bond means two electrons. So, here two electrons, one bond is formed. Here two electrons, one bond is formed. How many are there out of sixteen? Four.

Still the octet is incomplete. It is not done. One, two, three, four. Do more.

Five, six, seven, eight. Eight out of sixteen are used. Now, can I make a third bond? Why? Because the carbon octet is complete.

It is not oxygen, but the carbon octet is complete. I can't make a bond between these two. But I have the remaining electrons. I have used 8 out of 16. How many are left? 8. Now the remaining electrons, the oxygen, how will we complete their octet?

They will be in the form of lone pair. Do you understand this point? So the bond that is formed is a bond pair.

The one that is not formed is a lone pair. Now count it, total 16 electrons will be formed and all the atoms will have their octet completed. That means everything is stable and ultimately the molecule will also be stable. If we make a bond and its structure, how will it be formed?

Double bond will form between carbon and oxygen and lone pair will form, two by two. Do you understand this? So calculate the number of valence electrons, decide the central atom, then distribute those electrons between those atoms.

First of all, single bond will be formed between all atoms. Even then, if electrons are left, then make multiple bonds. Even then, if electrons are left, then if multiple bonds cannot be formed, then make lone pair. But the condition is only one, that octet or duplicate should be complete. Is it clear?

Have you practiced CPP? Take it out. Let's discuss CO3 2-once so that you can also get iron.

Try to make the Lewis structure of carbonate iron. CO3 2-Yes, carbonate iron. Try to draw its Lewis structure.

CO3 2- Try, it will be wrong, what else will happen? Done? Copy me.

The first step is to calculate electrons. How many are there? 4 plus 6 into 3 plus 2. Because it is a negative charge. How many are there?

We have to distribute 24 electrons. Now, who will be the central atom of carbon and oxygen? Carbon. So, you wrote carbon. And how many oxygen do you have to apply?

Three. So, one It will be a single bond between all of them. So make a single bond. That means you have distributed 1, 2, 3, 4, 5, 6 electrons. Carbon can make one more bond because its octet is not complete.

So make one more bond in any of them. Anywhere. So here you have made one more bond.

Now the octet of carbon is complete. No more bond can be made. Now what will happen?

Lone pair. This oxygen has 4 electrons. Put it on the loam.

5, 6, 7, 8. Octet complete. It has just worked with 2 electrons. So 1, 2, 3, 4, 5, 6. It has the same condition.

1, 2, 3, 4, 5, 6. Count it. It has 24. Now this one and this one which is oxygen, they have made less bonds. How many bonds do we need to make?

Two. But what is the amount of bond they have made? Less.

What is the electron density on these? More. So, on this also minus charge will come and on this also minus charge will come. And what will this become? CO32 minus.

Is this point coming in your mind? They had 6 electrons. How many electrons did they have to use?

Two electrons. But they could only use one electron. Due to carbon.

So what is the electron density on these? If it is more, then there will be a negative charge. Is everyone clear?

Make ammonium ion. NH4+. NH4 plus ammonium ion.

Done? Total electrons? 8. How many are there in this?

5 plus 4 minus 1. Because it is the charge of plus 1. How many total electrons do you have to distribute? 8. Who will be in the center? Hydrogen cannot be there. No option is left.

Nitrogen has to be there. So, nitrogen in the middle. And you have to apply 4 hydrogen.

You can apply it any way. It is not necessary. 1, 2, 3, 4. Apply it like this also. No problem. The actual structure will come forward.

Okay. There will be a bond between all. So, we made one bond.

How many electrons were used? 1, 2, 3, 4, 5, 6, 7, 8. How many electrons were to be distributed? 8. But this positive charge remained. On which? On nitrogen.

Because nitrogen makes 3 bonds. It used its lone pair more than its capacity. What is the atomic number of nitrogen? 7. What is the configuration?

1 is 2. 2s2 2p 3 How many electrons does it have in the outermost? 5 Valency, calculate it normally 8-5, how many comes? 3 How many bonds does it make? 3 One lone pair remains on it But in this species, it has used its lone pair as well That's why it made the fourth bond That means, what happened to its electron density? Less That's why it will get a positive charge So, the positive charge in ammonium is coming on nitrogen.

We will study this further. It has a co-ordinate bond. We will study this further. But, we are understanding the Lewis structure.

The duplet of hydrogen is completed. The octet of nitrogen is completed. Clear?

Now, take out CPP. Do the first question. Sulphate iron. Make sulphate iron.

Have you got CPP? Do it. What is the valency of sulphur? 8 Sulfur belongs to the oxygen family only, right?

So, the amount of valence electrons in oxygen, will be in sulphur only. 6 Don't forget the periodic table. It will be with you all your life. Dear, it will be with you all your life. How can you not take it?

You have to take it. Now you will say, ma'am, we will do job or business, so how will our periodic table work in that? But you will grow further. Will you get married?

Even if you don't, it's okay. You will have kids. Will you teach them chemistry?

You will make them learn too. You will make them learn. Periodic table will work together. Make it. SO 4 2-No one could make it.

I am calling you now to make you on board. Tell the truth. I do very few questions. I have heard that you have more questions than me in other classes.

It doesn't happen. You are lying. Mr. Yogesh does a lot of questions.

Doesn't he? He does, right? No problem. Okay, like this?

Like this? Okay. Anyone? So, the next statement is that you also don't apply it. This is the next statement.

You also don't apply it. He has never applied it, you also don't apply it. Okay, SO4-2. Tell me honestly, who didn't make it?

It didn't shine at all, what is to happen? There is nothing to be ashamed of, nothing to be hesitated about. If it is not being made, then it is not being made. It is not being made.

I don't understand at all. But it is not being made. Any more? What about the rest?

What is the first step to be done? Number of electrons calculate. Step is same.

So, in sulfur and oxygen, it is equal. Six Pfizer is 30. Plus two. How many are there? 32. You have to distribute 32 electrons in it.

You must have taken it wrong. Sulfur and oxygen belong to the same family. Both have 6 valence electrons. Minus, yes. You have to do plus 2. Now who will be in the center?

Sulfur. Distribute 4 oxygens around it as you want to write. Single bond will definitely be made.

Make it. Now, is the sulfur coctet complete? No, it's not? It's done, right?

The other remaining electrons? What? What will you make? Will it be made?

You tell me. Tell me. Loan pair, double bond, Lewis structure. Lewis structure.

Where will it be made? Where is the scope? 1, 2, 3, 4, 5, 6, 7, 8. 8 Sulfur Octade is completed. Now, Let me apply Lone pair of Oxygen. Let me apply Lone pair of Oxygen.

How many should I apply? 6-6. Let's apply.

How many are there? Charge. A linear structure will be formed. How linear? Yes.

Sulphur and oxygen. This side. Both sides.

Okay. Then? One more oxygen on this side.

Now what should I do? Should I make a bond between them? How many? Single.

Then? Should I make a double here? No, it won't be like this.

You made it, right? You all told me the answer, right? You were telling the answer, B.

How did you get B? You told me the answer, B. How did you get B?

Number of loan pair and bond pair in SO2. SO4, 2 minus. Huh? If we make a bond pair of 4, then the bond pair is 4. 1, 2, 3, 4. And how much is the loan pair?

12. So, how much is the answer? 12 and 4. But where is 2 minus? Sulphur will be applied.

2 minus. Sulph is there. In other structure, oxygen is applied. It looks like this.

Actually, it is there. Because what can sulphur do to its valency? Expand. Right?

By the way, how much is the normal valency like oxygen? 2 How much is the normal valency like oxygen? 2 So how many bonds should sulfur actually make?

2 But in that 3D So it can expand its valency So what does it do with 2 electrons, 2 oxygens? It makes a double bond And each single single one gets charged on them This is the actual structure This is actual. But keep in mind that you are asked this question.

For example, let's talk about this. He asks how many sigma bonds and how many pi bonds are there in the Lewis structure. This is SO. Or just talk about SO. Understand this question very carefully.

This question has come up many times. How many sigma and how many pi bonds are there in the Lewis structure of SO? How do we make SO? Like this. Because sulphur can expand its balance, it can go up to 6 bonds.

Plus 6 is the oxidation state of it. Now accordingly, 1 sigma, i.e. 3 sigma and 1 pi. How many are there? 3 pi.

And this is done in the option. But in the question, it is written in its Lewis structure. In its Lewis structure.

So in the Lewis structure, more than 8 electrons. No, it won't. Lewis structure and how will it be made?

Like this. On this, it came minus, on this it came 2 plus, overall neutral. I will tell you the same thing in that experiment. On this, it came minus and on this it came, it made two more bonds.

It made two more bonds, so on this it came 2 plus. They have made one less bond, so on this it came minus minus. Overall it became neutral. Is this point clear?

Now tell me how much is sigma and how much is pi? 3 sigma and 1 pi. This is the correct answer.

Because in the question it is written in the Lewis structure of SO. If it is written only in SO, then it would be different. It is written in the Lewis structure of SO.

So this answer will come. It will be in both the options. Now we will do the same thing here. Sulfur has to make two bonds, usually, but it has made four.

It has made two more, but its electron density has decreased. How much has decreased? This much has decreased.

And all of them have made one less bond. All of them have made one less bond. So, minus, minus, minus, minus.

Now, tell me, how much is the total? Minus two. Now, do you understand how minus two has come? Sulfur has made more than its capacity.

So the charge is positive. Oxygen is made less than its capacity. So negative charge is minus 4 plus 2. What will be the total? Minus 2. But if bond pair and lone pair will ask, then count and tell.

If sigma-bi will ask, then see and tell what is single bonded and double bonded. Are you understanding the question? So if the Lewis structure is written in the question, then answer accordingly. Huh? Son, the usual normal valency of sulphur is 2, right?

What is the configuration of sulphur? 2, 8, 6. What is its valency? How many bonds does it make?

Covalent bonds have covalency of 2, right? Covalent bonds have to make it 2. But because it had 6 electrons in valence, 4 electrons were there which it could use, but usually, it doesn't. What did it do in this?

In some... So, we used all of them. So, the capacity was 2 but how many bonds did we make? 4. So, we made more than 2 bonds with our capacity.

On this, the electron density will decrease. See, there is no lone pair of this. If there was a lone pair, then the charge density would have been more. If there is no lone pair, then the charge density has decreased. So, the charge has come positive.

How much positive? The more extra bonds we made. If we made 2 extra, then it is 2+.

Oxygen had to be used but it didn't. If it's not used, then the charge density is higher, so the charge is minus. Is this concept clear to everyone? Now what do you have to do after going home?

You have to do your CPP and bring it in the next class.

Transcript for:Understanding Ionic and Covalent Compounds

Transcript for:
Understanding Ionic and Covalent Compounds