Understanding Chemical Bonding Concepts

Hello my shimmering stars, today I sure I grew will welcome you all to this amazing platform of PW English. So students I welcome you all to your nexus batch and today we are going to start with a new chapter that is chemical bonding. So students I hope so you have seen the previous lecture, the previous chapter and it was quite clear to you all. Now today we are going to proceed to a new beginning that is going to be chemical bonding. And let me tell you, this is going to be the most interesting chapter of yours of class 11th standard. So before starting the students, I have few lines for you. Please listen to it very, very carefully. The greatest glory in living lies not in never falling. The greatest glory in living lies not in never falling, but in rising every time we fall. So students, when so ever you feel in life that yes it is the hardest phase or you are not able to do anything, just remember that this is the phase where you have to stand up again and then you have to move further. And when you will move further with that confidence that yes, no matter what has happened, no matter I am not getting the topic, no matter you know it is the hardest time but I am you know not giving up and standing and moving further, that phase of your life will make you the most you know stronger person that you can ever ever ever imagine so you will become more stronger than before yes students so with that we are going to start with our new chapter so i guess each and everybody of you are ready now what you have to do as if uh you know in this particular session in this particular chapter we are going to understand chemical bonding with you know animations with videos uh such as where overlapping is seen how hybridization takes place how do the structure look alike so we are going to do all of that in detail with the help of animations 3d animations okay and i guess this will be the most interesting one so students before starting this let me tell you what are the topics we are going to cover today in this particular session of ours see today's session is based upon the general introduction to the chapter chemical bonding as well as the session is particularly based upon modes of chemical bonding moreover we are going to cover the previous year questions of the chapter classification of elements and periodic properties as i've told you in the previous class that yes we will be solving the previous year questions we will be doing your homework questions okay and we will be also covering the new chapter so i guess you all are ready take your notebook take a water bottle stay hydrated yes students now let us start this session with a beautiful smile so ma'am as you already will know this is going to be your which lecture lecture number first on which chapter chemical bonding as well as we are going to practice some pyqs that means the previous year previous year questions that are asked in your competitive examination for the chapter periodic classification or classification of elements and the periodic properties okay students so the very first thing is first of all the very first initial topic is going to be introduction to chemical bonding okay The second part is going to be modes of bonding. The third segment will be about discussion of the homework questions. And the fourth segment will be based upon previous year questions and you know of the classification of elements and the periodic properties. So now we are going to start with our very first topic. But before that we have your friends with you. Kalsham and Beria waiting for you all students. So As I am saying Kalsham and Beryam I just remember that yes we have given you so many tricks in order to remember the periodic table. So have you revised the tricks? If not students don't miss that tricks topic. Go and learn the periodic table because again and again again and again you will be seeing that in the variation segment in in the previous chapter we had a variation topic variation in across the period along the group. So over there if you know the periodic table it will be easy for you but if you don't know the periodic table no it will create a you know a little bit of confusion a little bit of you know time consuming concept will be there because if you don't remember it you will waste your time so it's better go learn with the help of tricks the whole periodic table and if and sometimes what happens you're learning but you're not remembering yeah so what you can do is open up your questions start solving your questions practice more and more questions and then apply the trick over there see this is also another way to learn key concepts yes okay now Barium and Calcium are welcoming you here. So Calcium says, hello shimmering stars, have you revised yesterday's class? See she's so much concerned for your previous sessions. In each and every session, she's there and then she asks you that whether you have revised or not. So don't disappoint her, don't disappoint me, don't disappoint yourself. Yes, do revise each and every session, then only you can succeed in your life. Everybody knows the topic, everybody understands the topic but the concept is they don't revise it. okay and they lack over there and due to this they forget an examination see exam pressure is another you know fear right in order to conquer it in order to come out of it you have to do a lot of revision without revision you cannot be successful so she is there you know in each session to make you remember this that you have to revise now here barium says hi friends be ready for the new chapter yes okay So starting with the very first topic of ours that is going to be introduction to chemical bonding. Now my very first question is what is the chemical bond students? What do you feel is a chemical bond? See chemical word somewhat says about chemical reactions ma'am and bond is something where there is some kind of attraction or there is a line in between two atoms. Sorry a line between two atoms is a bond. or a thread between two atoms is a bond or what is a bond ma'am? But ma'am in you know books we have seen for example if it is written A B, A and B have a single line in between that is bond. No students, thread is not a bond, line is not a bond. What is a bond? Bond is basically the attraction between two atoms. Sort of bonding between two atoms. Now what kind of bonding between atoms? What kind of attraction between atoms? We are going to understand them. We are going to understand it. Now attraction can be like one positive and negative are attracted towards each other. That attraction in other terms is a bond. That sharing of electrons in other terms is a bond. That donating electrons and creating a bond you know sharing donating one atom is donating electrons and creating a bond right that is a bond. So bond is not a thread, bond is not a line, bond is basically sharing and making you know a complete molecule which has the octet complete. a configuration complete. So let us understand chemical bonding in detail. Now you will notice chemical, chemical is something related with chemical reactions, bond is something whereas there is attraction, there is sharing, we are going to understand it. There is transferring of electrons, so this is kind of bonds that we are going to observe, yeah. So ma'am if we'll talk in general, is there you know we are going to understand about types of bond over here, we are going to do that. one by one. So as I have already told you that from the word chemical bond, what comes in your mind? A thread, a bond, attraction. So what is a chemical bond? Chemical bond basically the attractive force which holds various constituents. Now the constituents over here can be atoms, can be ions, basically the particles together in different chemical species is called a chemical bond. So this is a simple definition that the attractive force which brings two atoms all together is a chemical bond. Quite simple, quite simple. If something is positive in nature and if something is negative in nature, they are coming together, they are sharing their electrons or they are attracting towards each other. That is the bond formation. The attractive forces between the constituent particles which leads to a formation of a particular molecule, a particular structure, a particular compound is a chemical bond. Yes everybody. Now students, um There are so many questions that comes in your minds. For example, why do atoms combine? This is a question which generally comes in students'mind. Why they are combining? What is the need to combine? If they won't combine, then we are not going to study anything. No, this is the joke. Jokes apart. Why do atoms combine? What is the reason behind them? In order to attain stability? In order to exist in a certain phase? in order to complete itself that there are many reasons yeah so we are going to do that in this particular chapter now what question is the next question that comes in your mind the next question is why are only certain combinations possible why only certain combinations are possible not you know there are some compounds there are some elements which don't you know form bonds they don't react why is it so what is the reason behind it next question that comes to your mind is Why do some atoms combine while certain others don't? What is the reason? Why not all the elements? Why not all the elements? Another question comes to your mind. Why do molecule possesses definite shape? What is the reason? Why do we calculate hybridization? All of these key concepts will be explained in this particular chapter with the help of Lewis dot structure, Lewis theory, with the help of Wasper theory. with the help of valence bond theory, hybridization, molecular orbital theory, these all topics will help you to attain the answers for this particular questions. Clear everybody? So now this was the introduction basically and these were yes the NCRT highlight as well. Now starting with the very first part over here, what is the chemical bond? Now before this, before this the types of bonds let us understand about the modes of chemical bonding. How does chemical bonding takes place? How does chemical bonding takes place? So chemical bonding Chemical bonding takes place by two ways. Chemical bonding takes place by two ways. The very first, the very first way, the A way is by, by sharing of electrons. No, first of all, right, first by transferring of electrons. The very first way is by transferring of electrons. So by transferring of electrons, you can see that yes, there is a chemical bond being formed. Now by transferring of electron, which kind of bond is being formed? By transferring of electron, you see ionic bond is being formed. Which kind of bond ma'am? Ionic bond is obtained. Okay. Okay. What is the next way? Another way? By sharing of electrons. By sharing of electrons. So by transferring of electrons, you create a chemical bond such as ionic bond. By sharing of electrons also, you create a bond. Now by sharing, how do you create a bond? Which kind of bonds? Over here, now you can obtain two kinds of bonds. The very first that you will obtain will be your covalent bond. And another one will be your coordinate bond. Another one will be your coordinate bond. So three kinds of bond we are now going to focus upon that is ionic bond, covalent bond, coordinate bond. Coordinate bond in other terms is dative bonds also. Now what are these? See a hint I have already provided you that when you transfer electrons you are going to obtain ionic bond. When you are sharing the electrons... you are going to obtain either the covalent or the coordinate one. Now we will explain, we will understand them one by one. Let us start with the very first kind of bond that is going to be your ionic bond. That is going to be your ionic bond. See if I will talk about ionic bond. Ionic bond is seen in the case of cations and anions. Cations and anions. Cations are the one which has positive charge. Anions are the ones which have negative charge. Yes. Now see in the case of ionic bond I already told you ketines and ions formation occurs. Let us take a general example. See this is just an introductory section okay. In the next lecture you are going to start with the very first topic and then you are going to understand. But in today's session you will understand what is chemical bonding, why do chemical bonding takes place, what is the cause behind them, how does it occur. So basic key concepts we are going to clear one by one. If you have not read anywhere, if you are starting from the very first time it will be very very helpful for you. coming back over here let us take an example of na cl how is na cl formed so we are going to understand about formation of na cl now see na cl contain two types of you know ions na cl contains two types of ions one is na positive another one is cl negative na positive cl negative na positive is your cation, Cl negative is your anion. So step by step we are going to understand them. First of all I want you all to write each and every line which I have written over here so that I can move on to the next part. Shall I move on to the next part? Shall I move on to the next part? Yes ma'am. Okay so see students now the very first step is the very first step is formation of formation of cation formation of cation now understand in the formation of cations that means the positively charged particles that means what happens see we know sodium na it has an atomic number 11 this what will be the configuration ma'am 1s2 2s2 2p6 3s1 now see How will this Na become stable? Na can become stable by losing one electron. Why I am saying that? See, if I have to fill all the electrons, 1s2, that means 2 electrons, 2s2, again it is 2 electrons, 2p6, so it is 1, 2, 3, oh sorry, 4, 5 and 6. Again it is completely filled. Now it is 3s1. Only one electron. See only one electron. So if we are going to lose this one electron it will attain a stable configuration which has you know paired electrons completely filled orbitals. So by losing one electron it becomes stable. By losing one electron it becomes it becomes stable. Yes. So what it will do? Na will lose one electron and will form what? It will form Na positive. What happens over here? Na will lose one electron and will form Na positive. When it will lose one electron, it will have a configuration of 1s2 2s2 2p6 which is stable. So here this is the formation of cation Na positive. Now why there is a positive charge if it is losing electron? For example, I am a neutral species. Neutral species is something which has equal positive, equal negative. Clear? If I am losing negative, I will be positive. Simple no? If I have equal positive and negative, I am neutral. I have no charge. If negative goes, I will be left with positive. So it becomes N-A positive. The next step. The second step. Second step is formation of. Second step is formation of anion. formation of an ion now see what happens now let us talk about chlorine chlorine chlorine has what atomic numbers to it's ma'am chlorine has 17 so we are going to write it see if we are going to write the electronic configuration for this as well it is going to be 1 s2 s2 2 b6 3 s2 see electrons 2 plus 2 4 4 plus 6 10 12 5 are left 3 p 5. Yes, everybody, 3 p 5. So, if we are going to fill electrons, it is 1 s 2, 2 s 2, 2 p 6. So, 1, 2, 3, 4, 5, 6, 3 s 2 and 3 p 5. So, 1, 2, 3, 4 and 5. It requires one electron. one more electron to become stable. It loses and becomes stable. It requires one electron to become stable. So by gaining one electron, by gaining one electron, it will, it will become stable. By gaining one electron, it will become stable. So what it will do? CL. will gain which electron? The electron being lost by Na. It will gain that electron which is loosed by Na, which is provided by Na. So, now this electron is gained by chlorine and it will form what? Cl negative. How Cl negative is seen? See when you are gaining one electron, electron carries a negative charge, electron carries with charge a negative charge. So what it will become? It will become Cl negative because if something is acquiring which kind of charge, something is acquiring a negative charge. Now see students over here. For example, I am a neutral species, I have positive and negative. If negative is coming to me, more negative is coming to me, I will become more negative. If positive is more coming to me, I will become more positive. Electron carries a negative charge. So, negative when comes it will gather a negative charge on it. Now, see what happens. Now, what we have formed till now? We have acquired Na positive. We have formed Cl negative. Right? So, now when this Na positive and Cl negative combines with each other they are going to form NaCl. They are going to form Na. Sorry. They are going to form NaCl. Now let us see with the help of Lewis dot structure also. No need to worry. Lewis dot structure I will explain you in the next class how to write it, how to draw it. But understand key concept. Now Na positive. Let us take an example. That means Na here has donated its electrons to chlorine to form this. Let us see with the help of Lewis representation also. See Na basically has how many valence electrons? Valence electrons is the outermost shell electron. it is one over here so you will represent only one electron that that means it carries one it has only one electron in the outermost shell now see here is chlorine and chlorine basically has how many electrons in the outermost shell outermost shell is third shell two electrons of s and five of p that means seven electrons here it has third shell outermost but only one electron here it has seven electrons so it is going to be one two three four five six and seven 7 electrons. Now what happens? We have just now seen that Na will donate its 1 electron to Cl and will form what? It will form NaCl. So Lewis dot representation we will understand in depth in the next class when we are going to understand about the Lewis theory. But over here I am telling you here ionic bond is seen. What is seen to you? Here which kind of bond exists? Ionic bond exists between what? Between, between cations and anions ma'am. That means between Na positive and Cl negative ma'am. So over here what is happening? Over here there is transferring of, over here there is transferring of electron that is taking place, right? so here you can even mention over here there is transferring of electron that is taking place clear everyone write down the very first case of transferring of electron this is an example of example of transferring of an electron Clear everybody. Clear everybody. That is formation of NaCl. In actual students, if I show you the 3D structure of NaCl, how does it looks like? So, see over here. For example, this is your Na, okay? It is surrounded by 6 chlorine. How in such a way? See, 1 chlorine will be here. One chlorine will be here, one will be here, one will be here, one at its back and one at its front. So this is back and front which I have represented by dotted line. So NaCl structure, the rock salt like structure you are going to observe in solid state chapter also in depth. Right? Clear everyone? Everybody please write it down so that I can start with now the sharing of electrons. This was the transferring of electrons. Now comes the sharing of electrons the next is the next is by sharing of electrons now see elements they not only transfer electrons they can also share the electrons in order to become stable Now they became stable because their electronic configuration were fulfilled. They can also become stable but by sharing of electrons. Let us take an example. First I am taking a case of your covalent bond. Of your covalent bond. So in the case of covalent bond I am taking an example of CH4. Now students you very well know about carbon. Carbon basically that carbon basically is atomic number six so it is 1s2 2s2 2p2 yes it is 1s2 2s2 2p2 it is combining with four hydrogen atoms though you will understand in the upcoming segment that what are hybrid orbitals how does hybridization takes place but in general i'm just discussing it normally carbon basically let me tell you one thing over here because for now you will think that only two electrons are there that two orbitals are empty so two bonds will be found no no they are not You will get to know about the hybridized orbital. But yes, you can understand this in this way that the valency of carbon is 4. Valency of carbon is 4. Now ma'am, what is valency? In the previous session, if you remember, I have already told you the definition for valency. Now, what was the definition for valency? right so valency students was basically the combining capacity the combining capacity of element what it was it was basically the combining capacity of any element that means it can combine with four elements that means with four hydrogens now let us consider for example we have this carbon carbon has valency four that means four are the electrons that are seen in the outermost shell because see 2 is the outermost shell it contains 2 electrons of S and 2 of P that means 4 electrons represented 4. Now let us talk about hydrogen. See students hydrogen basically atomic number 1 so it is 1 is 1. So 1 electron in the outermost shell so it is combining with 4 hydrogens and each hydrogen contains 1 1 electron in the outermost shell 1 1 electron in the outermost shell. So now see hydrogen when 1 it will gain 1 electron it will complete its duplicate. duplet is holding two electrons s orbital can maximum hold two electrons only so it will gather this electron see it is creating a bond by sharing this electrons see that's why i put in a circle two electrons stable it is sharing its electrons stable sharing its electrons table sharing its electrons table now let us talk about carbon carbon is having four electrons now it is also sharing this this this and this so one two three four five six seven eight that means eight electrons that means its octat is now complete So over here what are you observing? Here if we will see here we will see that it is sharing of electrons. It is what ma'am? It is sharing of electrons in order to in order to attain stability in order to attain stability. Now that can be attained in the way of getting an octade complete. or the duplet complete octat complete or getting the duplet complete this can be done in such a way so now in short you know why chemical bond is created in order to complete the doctor in order to attain the electronic configuration in order to become stable quite clear this was about the covalent bond covalent what in other terms is sharing of electrons in other terms is sharing of electrons ma'am now comes the second type that is coordinate bond now comes the second type that is coordinate bond see students coordinate bond is also referred to as data bond now understand in covalent bond two atoms are sharing the electrons with each other and creating a bond but in covalent bond one single atom is sharing its electrons and you know creating a bond in this two atoms are sharing the electrons and creating a bond but in coordinate only one atom is donating electrons and sharing electrons So in coordinate only one atom is sharing its electrons and creates a bond. For example if A has electrons and B doesn't have electrons so A will share the electrons with B. So when it is sharing. arrow will be made in such a way. That means A is sharing and A holds electrons. B does not have electrons. A is sharing its electrons with B. Clear everybody? Also in covalent bond it arises due to difference in electronegativity. One thing more you can add over here. Difference in electronegativity. Now you have already understood about the term electronegativity. In the previous class that is tendency to attract shared pair of electron towards itself. for coordinate bond in depth we will understand in the upcoming classes but yes this is a quick review of what is a coordinate bond clear everyone everybody please write it down everybody please mention it write it done that's great students that's really really very good now in short if i have to say chemical bond is categorized into now this is classification classification is done as ionic covalent and also metallic bonding see metallic bonding let me tell you it occurs between occurs between what? It occurs between kernels and free electrons. Now this we will understand in depth in the upcoming classes but yes you should know it occurs between kernels and the free electrons. Now also metallic bonding is also categorized into hydrogen bond and the wonderwalls bond. Hydrogen bond and the wonderwall force bond basically are intermolecular bonds. Okay. And the other one ionic bond, covalent bond, metallic they were interatomic bond. When the bonds are seen between atoms that are interatomic when the bonds are seen between molecules that is the intermolecular ones. Yeah. So one by one we will understand them but yes in the upcoming sessions. Right. So students now comes this ends our. the very first segment of ours that was discussion with regard to the chapter chemical bonding now we are coming to your chapter that is classification of elements and periodic properties so as i've already told you we are going to discuss the homework questions the most uh asked homework questions as there you may observe that one or two questions are not in the homework which i have not discussed over here because i have not seen any kind of doubt over there they were very simple questions so the questions which i felt yes you are facing an issue You know 90% homework questions are being solved over here if one or two questions are left. If you are not able to do so you can ask in the chat section as well. So starting with homework questions we will be doing NCRT in-text questions and then we will be doing the homework question and then the previous year questions. So let us start with the very first question of yours that is problem number 3.1 that is NCRT in-text question. Now from here from this particular page we are going to start with your homework discussion. This is your homework homework discussion for your chapter that is classification of elements that is classification of elements and periodic periodic properties clear So the very first homework question is written in front of you. Let us read it. That is problem 3.1. It says what would be the IUPSC name and the symbol for the element with atomic number 1 2 0. 1 2 0. 1 2 0. For 1 it is written as un. For 1 you write un. For 2 you will write by. For 0 you will write what? Yes. I have already told you that what have to what you have to write. For 0, you are going to write nil everybody. For 0, you will be writing what ma'am? Nil. Yes. For 1, it is un. For 2, it is by. For 3, it is try in such a way, right? For 0, it is nil. And at the last, you have to write yum. So, what it will be ma'am? It will be un, by, nil, yum. So, ma'am, this is the name for 120 atomic number and what are the symbols? The initial letters U, B, N. So, it is U, B, N. this is the symbol everybody write this homework question down so that we can move on to the next part done with this yes everybody done done done done done that's great next question comes now problem 3.3 the element z is equals to 117 and 120 have not been discovered yet in which family group would you place these elements and also give the electronic configuration in each case so it's very simple students if i'll talk about the Group number 117, it belongs to your halogen family. To which family ma'am? To halogen family. So it will have the same electronic configuration of the halogen family. That is going to be NH2NP7. Sorry, NH2NP5. That means 7 electrons in the autonomous shell. so this will have the same electronic configuration as this and over here if you'll see in the halogen family fluorine chlorine bromine iodine all of that all of that stuff 117th lies in the period number seventh so the outermost electronic configuration is going to be 7s2 7p5 clear everyone write it down students fast so that i can now move on to your 120 element Okay, so family we have already told it is halogen family. Group also they are asking it is group number 17. Then our next part is about 120. See 120 basically lies under alkaline earth metals. And if I will talk about the group that is growing to be your group number 2. And if I will talk about the configuration it will have NS2. 7S2. clear outermost configuration clear everyone moving on to the next question we have uh problem 3.4 considering the atomic number in the position in the periodic table arrange the following elements in the increasing order of metallic corrector which order metallic correct right we have been provided with silicon Beryllium, magnesium, sodium and phosphorus. Yes everybody, yes everyone. See sodium lies over here, magnesium over here. Okay and I'm just writing the order students. Okay in order to make you understand. Then we have it is like this no? Beryllium, magnesium, sodium, magnesium over here and then we are left with potassium and silicon yes sorry phosphorus and silicon not potassium so first of all there is no way to light lithium lithium i've written for the belly beryllium sake okay yeah So we require only sodium over here. Yeah. So this is going to be group number second. Now we require which which element? I am going to put tick over here. We require beryllium. We require sodium. We require magnesium. Right? Yeah. Among group 1 and group 2, these are the elements. Now we have to tell the metallic order students. So what will be the order as per the group students? What do you feel what is going to be the order? Anybody just think about it. Just think when you're moving across the group N along the period. See very simple thing if I have to tell you when I'm moving from top to bottom no metallic corrector will increase and when I'm moving from across a period metallic corrector decreases and non-metallic corrector increases. Okay let us talk about sulfur and silicon over here. not sulfur and silicon phosphorus and silicon again and again it comes out to other words yeah so phosphorus belongs to its family nitrogen family yeah nitrogen phosphorus and if i'll talk about your oxygen over here oxygen then we have silicon yeah no it silicon oxygen sulfur selenium tellurium polonium and if i'll talk about carbon over here for carbon we have carbon then silicon yes silicon germanium in such a way so here we require not carbon not silicon not oxygen not sulfur not selenium in this way this is the order now see when you're moving from top to bottom metallic character increase i am deleting other elements i am deleting all the other elements yeah see now we have this trend over here here see metallic character decreases that means this is going to be the order and from top to bottom it increases so this is going to be the order yeah so this is going to be the order we have total five elements this is going to be the order the highest one will be of whom and the highest one will be of sodium Then it will have a fume and then it will have a magnesium. After that what we will have? We will have beryllium and then we will have silicon and at last it will be phosphorus. So it is sodium, magnesium, beryllium, silicon and phosphorus. If you want to write it belongs to your carbon family that means your group number 14th, it belongs to your 15th group. Clear? And if it belongs to your group number 2nd, it belongs to group number 1st. By this way you can write it down. so clear students shall i move on to the next one done done done done done done done done great now in terms of period and group where would you locate the element with z is equals to 114 now i guess this back exercise question we have already discussed in the class yeah this we have already done with 114. now comes the questions which i have given you as a homework in the long form of periodic table all the non-metals are placed under the very first is s block p block d block f block so very simple all the non-metals are placed under the p block family now only we have seen that when we are moving across a period that means from left hand side to the right hand side my metallic character is going to metallic character is going to decrease that means non-metallic character non-metallic character will increase. So that means all the non-metals are placed under the right-hand side of the periodic table that is p-block elements. Hence answer comes out to be option number b. Clear everyone? Shall I move on to the next question? Everybody write it down. Everybody write it down so that I can start with my next question now. Done students? Okay here comes your next question which is which is a metalloid? P, B, S, B, B, I and Z. So students quite easy option number B is the right answer. What is the metalloid which holds the properties of metals as well as non-metals? Clear? Simple question. Moving on to the next one. The element with atomic number 15. 55 belongs to which block s block p block d block f block so i can write the configuration or not if you know the uh let us talk about group number one see it has atomic number one now you have to use the magic trick 2 8 8 18 18 32 so add 2 into 1 you will get 3 you add 8 into 3 you will get 11 add again 8 you will get 19 add now 18 into it you will get what 37 now add again 18 you will get what 55 so cesium basically is the element which has atomic number 55 and it belongs under the s block element so the answer comes out to be option number a as it is cesium Clear everybody. Write it down so that I can move on to the next question of ours. Done students. That's great. Now students come which of the following alkali metals has smallest size? Now alkali metals. What are alkali metals? It is basically hydrogen, lithium, sodium, potassium, rubidium, cesium and francium. so see when you're moving from top to bottom in a group what happens ma'am number of shells increases if number of shells are increasing atomic size will also increase ma'am if atomic size is increasing so this is going to be the order so the least one will be hydrogen is hydrogen there no lithium there no then we have sodium so answer here comes out to be option c Answer here comes out to be option number C. Clear everyone? Smallest size. Clear? Let us see the next question now. Which of the following ionic species has largest size? Now this is the different kind of question. Many of you will say ma'am now only we have seen top to bottom lithium will have the smallest size. See lithium students do has a smallest size but it can be hydrated. It is heavily hydrated. It is heavily hydrated. It is heavily hydrated and if it is heavily hydrated then lithium positive ion in aqueous form will have the largest size. It will acquire largest size if it is heavily hydrated. The smallest size will have the largest you know size in aqueous medium because it will be heavily hydrated. That means lithium aqueous will be the right answer. Hence option number D is the right answer everybody. Everybody write it down so that I can move on to the next question now. Shall I? Done students. Okay. Now comes chloride, iron and potassium ions are isoelectronic then. Isoelectronic refers to as the one which has same electrons. So if they have same electrons then which of the following is right? A. Their sizes are small. B. Cl-ine is bigger than K-ine. C. K-ine is relatively bigger. D. Their sizes depend upon other cation anions. See, if they have same number of electrons, then you always have to remember anion size will be greater than the cations one. Cations are smaller. So, anions are negatively charged. So, that means anions are, that means Cl negative is bigger than the K positive one. So, B option is going to be the right answer. Let us see the next question. Smallest among these species are? Very simple. Now only we have seen top to bottom number of shells increases. So, the size is going to be increasing, right? if size is increasing hydrogen will have the least smallest size so smallest among these species is hydrogen the next is it's time for the previous year questions students now we have completed basically our you know we have finished our homework session over here i hope so now your homework queries are clear now we are starting with the previous year questions the very first is the iupsc name of an element with atomic number 119 is going to be what now see this is the previous yearly asked question from for different competitive exams Starting with 119 atomic number for 1 we are going to write un again for 1 we will write un for 9 we are going to write e double n. So it is going to be un un in em em. So this is going to be the name un un in em that means ma'am option number a is going to be the right answer. Option number A is going to be the right answer. Clear everybody? Everybody please write it down. Done? Okay. Let us see the next question. Next question is the electronic configuration of an element is this much. What is the atomic number of the element which is just below the above element in the periodic table? See what are the number of electrons? First of all see 1s2 2s2 2p6 3s2 3p3 that means 2 plus 2 4 4 plus 6 10 10 plus 2 12. 12 plus 3 is how much? 12 plus 3 is 15. 12 plus 3 is 15. Yes, everybody. So, what do you feel? To which group it would lie? It is 2s2 3p3. 2s2 3p3. Which family? Which family? Nitrogen, phosphorus. Yeah? So, oversee. Nitrogen has an atomic number 7. If you will add 18 to it, it will become 15 p-block elements. So phosphorus, nitrogen phosphorus, then arsenic, then antimony and then bismuth. So then you are going to add what? You are going to add what? 18. If you are going to add 18, what you will get? 33. If you are going to add 18, what are you going to get? 33. That means the next element arsenic will have an atomic number 33. Simple, easy. Shall I move on to the next question if it is done students? Yes, everyone. If it is done, can I move on to the next question of yours? Everybody write it down for once. If the atomic number of an element is 33, it will be placed in the periodic table in what? Now only we have seen 33 element is basically, it lies under which period? 33, 1. Now only we have seen, no? It is 33 element. It lies under the P block element. It lies under the group number 15th. Right? That means the 5th group. Group number 15th is basically the 5th group. So, option number C is the right answer. Clear everyone? Option number C is the right answer. 5th group or 15th group? 5th group or 15th group? Clear? Next is? Which of the following oxides is most acidic in nature? Most acidic in nature. Let me tell you students, BEO is most acidic in nature. Why? Because metallic character as we move from top to bottom increases. If metallic character basically increases, that means basic character is increasing, right? So, most acidic will be BEO. Clear? Moving on to the next question now. Among the elements, calcium, magnesium, phosphorus and chlorine, the order of increasing atomic radii. Now, this is... A kind of a question that is your homework for now. Yes, this is your first homework question for today. Your first homework question because see atomic radii hold some variations, some of the exceptions. So I want you all to try by your own as well. So this is first homework question. Among the elements calcium, magnesium, phosphorus and chlorine, the order of increasing atomic radii is what? A option, magnesium have the least, then calcium, chlorine, phosphorus. B is chlorine, phosphorus, magnesium, calcium. C is phosphorus, chlorine, calcium, magnesium. D is calcium, magnesium, phosphorus and chlorine. Moving on to the next question. Which of the following has the largest size? Very simple. Anion will have the largest then the parent atom then will be the cation. So anion that means Na negative then it will be Na and at last it will be cation, Na positive. So this is going to be the order. Which has the largest radii? Option number C will have the largest radii. Next. Which of the following has maximum electron affinity? Yes students, now we very well know fluorine, chlorine, bromine, iodine electron affinity basically. When we move down the group, what happens to that? It is going to decrease because size increasing but there is an exception, chlorine will have the highest electron affinity. So option number D among the following is going to be the right answer. Yes, so yes students here we are going to end our today's class. I hope so your today's class was helpful for you. You were able to solve questions, you were able to understand about chemical bonding but now in the next lecture we are going to do a lot of structure based questions, a lot of structure based concepts. So be prepared for that session and yes do revise your previous chapter because revision is really really very essential if you are preparing for any competitive exam. Now students we shall meet you in the next class. Till then keep smiling, keep learning. Thank you so much my dear students. Take care. Bye bye. Thank you.

Now today we are going to proceed to a new beginning that is going to be chemical bonding. And let me tell you, this is going to be the most interesting chapter of yours of class 11th standard. So before starting the students, I have few lines for you. Please listen to it very, very carefully. The greatest glory in living lies not in never falling.

The greatest glory in living lies not in never falling, but in rising every time we fall. So students, when so ever you feel in life that yes it is the hardest phase or you are not able to do anything, just remember that this is the phase where you have to stand up again and then you have to move further. And when you will move further with that confidence that yes, no matter what has happened, no matter I am not getting the topic, no matter you know it is the hardest time but I am you know not giving up and standing and moving further, that phase of your life will make you the most you know stronger person that you can ever ever ever imagine so you will become more stronger than before yes students so with that we are going to start with our new chapter so i guess each and everybody of you are ready now what you have to do as if uh you know in this particular session in this particular chapter we are going to understand chemical bonding with you know animations with videos uh such as where overlapping is seen how hybridization takes place how do the structure look alike so we are going to do all of that in detail with the help of animations 3d animations okay and i guess this will be the most interesting one so students before starting this let me tell you what are the topics we are going to cover today in this particular session of ours see today's session is based upon the general introduction to the chapter chemical bonding as well as the session is particularly based upon modes of chemical bonding moreover we are going to cover the previous year questions of the chapter classification of elements and periodic properties as i've told you in the previous class that yes we will be solving the previous year questions we will be doing your homework questions okay and we will be also covering the new chapter so i guess you all are ready take your notebook take a water bottle stay hydrated yes students now let us start this session with a beautiful smile so ma'am as you already will know this is going to be your which lecture lecture number first on which chapter chemical bonding as well as we are going to practice some pyqs that means the previous year previous year questions that are asked in your competitive examination for the chapter periodic classification or classification of elements and the periodic properties okay students so the very first thing is first of all the very first initial topic is going to be introduction to chemical bonding okay The second part is going to be modes of bonding. The third segment will be about discussion of the homework questions. And the fourth segment will be based upon previous year questions and you know of the classification of elements and the periodic properties.

So now we are going to start with our very first topic. But before that we have your friends with you. Kalsham and Beria waiting for you all students. So As I am saying Kalsham and Beryam I just remember that yes we have given you so many tricks in order to remember the periodic table.

So have you revised the tricks? If not students don't miss that tricks topic. Go and learn the periodic table because again and again again and again you will be seeing that in the variation segment in in the previous chapter we had a variation topic variation in across the period along the group. So over there if you know the periodic table it will be easy for you but if you don't know the periodic table no it will create a you know a little bit of confusion a little bit of you know time consuming concept will be there because if you don't remember it you will waste your time so it's better go learn with the help of tricks the whole periodic table and if and sometimes what happens you're learning but you're not remembering yeah so what you can do is open up your questions start solving your questions practice more and more questions and then apply the trick over there see this is also another way to learn key concepts yes okay now Barium and Calcium are welcoming you here. So Calcium says, hello shimmering stars, have you revised yesterday's class?

See she's so much concerned for your previous sessions. In each and every session, she's there and then she asks you that whether you have revised or not. So don't disappoint her, don't disappoint me, don't disappoint yourself.

Yes, do revise each and every session, then only you can succeed in your life. Everybody knows the topic, everybody understands the topic but the concept is they don't revise it. okay and they lack over there and due to this they forget an examination see exam pressure is another you know fear right in order to conquer it in order to come out of it you have to do a lot of revision without revision you cannot be successful so she is there you know in each session to make you remember this that you have to revise now here barium says hi friends be ready for the new chapter yes okay So starting with the very first topic of ours that is going to be introduction to chemical bonding.

Now my very first question is what is the chemical bond students? What do you feel is a chemical bond? See chemical word somewhat says about chemical reactions ma'am and bond is something where there is some kind of attraction or there is a line in between two atoms.

Sorry a line between two atoms is a bond. or a thread between two atoms is a bond or what is a bond ma'am? But ma'am in you know books we have seen for example if it is written A B, A and B have a single line in between that is bond. No students, thread is not a bond, line is not a bond. What is a bond?

Bond is basically the attraction between two atoms. Sort of bonding between two atoms. Now what kind of bonding between atoms?

What kind of attraction between atoms? We are going to understand them. We are going to understand it. Now attraction can be like one positive and negative are attracted towards each other.

That attraction in other terms is a bond. That sharing of electrons in other terms is a bond. That donating electrons and creating a bond you know sharing donating one atom is donating electrons and creating a bond right that is a bond.

So bond is not a thread, bond is not a line, bond is basically sharing and making you know a complete molecule which has the octet complete. a configuration complete. So let us understand chemical bonding in detail. Now you will notice chemical, chemical is something related with chemical reactions, bond is something whereas there is attraction, there is sharing, we are going to understand it. There is transferring of electrons, so this is kind of bonds that we are going to observe, yeah.

So ma'am if we'll talk in general, is there you know we are going to understand about types of bond over here, we are going to do that. one by one. So as I have already told you that from the word chemical bond, what comes in your mind?

A thread, a bond, attraction. So what is a chemical bond? Chemical bond basically the attractive force which holds various constituents.

Now the constituents over here can be atoms, can be ions, basically the particles together in different chemical species is called a chemical bond. So this is a simple definition that the attractive force which brings two atoms all together is a chemical bond. Quite simple, quite simple.

If something is positive in nature and if something is negative in nature, they are coming together, they are sharing their electrons or they are attracting towards each other. That is the bond formation. The attractive forces between the constituent particles which leads to a formation of a particular molecule, a particular structure, a particular compound is a chemical bond. Yes everybody.

Now students, um There are so many questions that comes in your minds. For example, why do atoms combine? This is a question which generally comes in students'mind.

Why they are combining? What is the need to combine? If they won't combine, then we are not going to study anything. No, this is the joke. Jokes apart.

Why do atoms combine? What is the reason behind them? In order to attain stability?

In order to exist in a certain phase? in order to complete itself that there are many reasons yeah so we are going to do that in this particular chapter now what question is the next question that comes in your mind the next question is why are only certain combinations possible why only certain combinations are possible not you know there are some compounds there are some elements which don't you know form bonds they don't react why is it so what is the reason behind it next question that comes to your mind is Why do some atoms combine while certain others don't? What is the reason?

Why not all the elements? Why not all the elements? Another question comes to your mind.

Why do molecule possesses definite shape? What is the reason? Why do we calculate hybridization? All of these key concepts will be explained in this particular chapter with the help of Lewis dot structure, Lewis theory, with the help of Wasper theory.

with the help of valence bond theory, hybridization, molecular orbital theory, these all topics will help you to attain the answers for this particular questions. Clear everybody? So now this was the introduction basically and these were yes the NCRT highlight as well.

Now starting with the very first part over here, what is the chemical bond? Now before this, before this the types of bonds let us understand about the modes of chemical bonding. How does chemical bonding takes place?

How does chemical bonding takes place? So chemical bonding Chemical bonding takes place by two ways. Chemical bonding takes place by two ways.

The very first, the very first way, the A way is by, by sharing of electrons. No, first of all, right, first by transferring of electrons. The very first way is by transferring of electrons.

So by transferring of electrons, you can see that yes, there is a chemical bond being formed. Now by transferring of electron, which kind of bond is being formed? By transferring of electron, you see ionic bond is being formed. Which kind of bond ma'am? Ionic bond is obtained.

Okay. Okay. What is the next way?

Another way? By sharing of electrons. By sharing of electrons.

So by transferring of electrons, you create a chemical bond such as ionic bond. By sharing of electrons also, you create a bond. Now by sharing, how do you create a bond? Which kind of bonds?

Over here, now you can obtain two kinds of bonds. The very first that you will obtain will be your covalent bond. And another one will be your coordinate bond.

Another one will be your coordinate bond. So three kinds of bond we are now going to focus upon that is ionic bond, covalent bond, coordinate bond. Coordinate bond in other terms is dative bonds also. Now what are these? See a hint I have already provided you that when you transfer electrons you are going to obtain ionic bond.

When you are sharing the electrons... you are going to obtain either the covalent or the coordinate one. Now we will explain, we will understand them one by one. Let us start with the very first kind of bond that is going to be your ionic bond. That is going to be your ionic bond.

See if I will talk about ionic bond. Ionic bond is seen in the case of cations and anions. Cations and anions. Cations are the one which has positive charge. Anions are the ones which have negative charge.

Yes. Now see in the case of ionic bond I already told you ketines and ions formation occurs. Let us take a general example.

See this is just an introductory section okay. In the next lecture you are going to start with the very first topic and then you are going to understand. But in today's session you will understand what is chemical bonding, why do chemical bonding takes place, what is the cause behind them, how does it occur.

So basic key concepts we are going to clear one by one. If you have not read anywhere, if you are starting from the very first time it will be very very helpful for you. coming back over here let us take an example of na cl how is na cl formed so we are going to understand about formation of na cl now see na cl contain two types of you know ions na cl contains two types of ions one is na positive another one is cl negative na positive cl negative na positive is your cation, Cl negative is your anion. So step by step we are going to understand them. First of all I want you all to write each and every line which I have written over here so that I can move on to the next part.

Shall I move on to the next part? Shall I move on to the next part? Yes ma'am. Okay so see students now the very first step is the very first step is formation of formation of cation formation of cation now understand in the formation of cations that means the positively charged particles that means what happens see we know sodium na it has an atomic number 11 this what will be the configuration ma'am 1s2 2s2 2p6 3s1 now see How will this Na become stable?

Na can become stable by losing one electron. Why I am saying that? See, if I have to fill all the electrons, 1s2, that means 2 electrons, 2s2, again it is 2 electrons, 2p6, so it is 1, 2, 3, oh sorry, 4, 5 and 6. Again it is completely filled. Now it is 3s1. Only one electron.

See only one electron. So if we are going to lose this one electron it will attain a stable configuration which has you know paired electrons completely filled orbitals. So by losing one electron it becomes stable. By losing one electron it becomes it becomes stable.

Yes. So what it will do? Na will lose one electron and will form what? It will form Na positive. What happens over here?

Na will lose one electron and will form Na positive. When it will lose one electron, it will have a configuration of 1s2 2s2 2p6 which is stable. So here this is the formation of cation Na positive. Now why there is a positive charge if it is losing electron? For example, I am a neutral species.

Neutral species is something which has equal positive, equal negative. Clear? If I am losing negative, I will be positive. Simple no? If I have equal positive and negative, I am neutral.

I have no charge. If negative goes, I will be left with positive. So it becomes N-A positive.

The next step. The second step. Second step is formation of. Second step is formation of anion. formation of an ion now see what happens now let us talk about chlorine chlorine chlorine has what atomic numbers to it's ma'am chlorine has 17 so we are going to write it see if we are going to write the electronic configuration for this as well it is going to be 1 s2 s2 2 b6 3 s2 see electrons 2 plus 2 4 4 plus 6 10 12 5 are left 3 p 5. Yes, everybody, 3 p 5. So, if we are going to fill electrons, it is 1 s 2, 2 s 2, 2 p 6. So, 1, 2, 3, 4, 5, 6, 3 s 2 and 3 p 5. So, 1, 2, 3, 4 and 5. It requires one electron.

one more electron to become stable. It loses and becomes stable. It requires one electron to become stable. So by gaining one electron, by gaining one electron, it will, it will become stable. By gaining one electron, it will become stable.

So what it will do? CL. will gain which electron? The electron being lost by Na. It will gain that electron which is loosed by Na, which is provided by Na. So, now this electron is gained by chlorine and it will form what?

Cl negative. How Cl negative is seen? See when you are gaining one electron, electron carries a negative charge, electron carries with charge a negative charge.

So what it will become? It will become Cl negative because if something is acquiring which kind of charge, something is acquiring a negative charge. Now see students over here.

For example, I am a neutral species, I have positive and negative. If negative is coming to me, more negative is coming to me, I will become more negative. If positive is more coming to me, I will become more positive.

Electron carries a negative charge. So, negative when comes it will gather a negative charge on it. Now, see what happens.

Now, what we have formed till now? We have acquired Na positive. We have formed Cl negative. Right? So, now when this Na positive and Cl negative combines with each other they are going to form NaCl.

They are going to form Na. Sorry. They are going to form NaCl. Now let us see with the help of Lewis dot structure also.

No need to worry. Lewis dot structure I will explain you in the next class how to write it, how to draw it. But understand key concept. Now Na positive. Let us take an example.

That means Na here has donated its electrons to chlorine to form this. Let us see with the help of Lewis representation also. See Na basically has how many valence electrons?

Valence electrons is the outermost shell electron. it is one over here so you will represent only one electron that that means it carries one it has only one electron in the outermost shell now see here is chlorine and chlorine basically has how many electrons in the outermost shell outermost shell is third shell two electrons of s and five of p that means seven electrons here it has third shell outermost but only one electron here it has seven electrons so it is going to be one two three four five six and seven 7 electrons. Now what happens? We have just now seen that Na will donate its 1 electron to Cl and will form what? It will form NaCl.

So Lewis dot representation we will understand in depth in the next class when we are going to understand about the Lewis theory. But over here I am telling you here ionic bond is seen. What is seen to you?

Here which kind of bond exists? Ionic bond exists between what? Between, between cations and anions ma'am. That means between Na positive and Cl negative ma'am. So over here what is happening?

Over here there is transferring of, over here there is transferring of electron that is taking place, right? so here you can even mention over here there is transferring of electron that is taking place clear everyone write down the very first case of transferring of electron this is an example of example of transferring of an electron Clear everybody. Clear everybody.

That is formation of NaCl. In actual students, if I show you the 3D structure of NaCl, how does it looks like? So, see over here. For example, this is your Na, okay? It is surrounded by 6 chlorine.

How in such a way? See, 1 chlorine will be here. One chlorine will be here, one will be here, one will be here, one at its back and one at its front. So this is back and front which I have represented by dotted line. So NaCl structure, the rock salt like structure you are going to observe in solid state chapter also in depth.

Right? Clear everyone? Everybody please write it down so that I can start with now the sharing of electrons. This was the transferring of electrons.

Now comes the sharing of electrons the next is the next is by sharing of electrons now see elements they not only transfer electrons they can also share the electrons in order to become stable Now they became stable because their electronic configuration were fulfilled. They can also become stable but by sharing of electrons. Let us take an example. First I am taking a case of your covalent bond.

Of your covalent bond. So in the case of covalent bond I am taking an example of CH4. Now students you very well know about carbon. Carbon basically that carbon basically is atomic number six so it is 1s2 2s2 2p2 yes it is 1s2 2s2 2p2 it is combining with four hydrogen atoms though you will understand in the upcoming segment that what are hybrid orbitals how does hybridization takes place but in general i'm just discussing it normally carbon basically let me tell you one thing over here because for now you will think that only two electrons are there that two orbitals are empty so two bonds will be found no no they are not You will get to know about the hybridized orbital.

But yes, you can understand this in this way that the valency of carbon is 4. Valency of carbon is 4. Now ma'am, what is valency? In the previous session, if you remember, I have already told you the definition for valency. Now, what was the definition for valency?

right so valency students was basically the combining capacity the combining capacity of element what it was it was basically the combining capacity of any element that means it can combine with four elements that means with four hydrogens now let us consider for example we have this carbon carbon has valency four that means four are the electrons that are seen in the outermost shell because see 2 is the outermost shell it contains 2 electrons of S and 2 of P that means 4 electrons represented 4. Now let us talk about hydrogen. See students hydrogen basically atomic number 1 so it is 1 is 1. So 1 electron in the outermost shell so it is combining with 4 hydrogens and each hydrogen contains 1 1 electron in the outermost shell 1 1 electron in the outermost shell. So now see hydrogen when 1 it will gain 1 electron it will complete its duplicate.

duplet is holding two electrons s orbital can maximum hold two electrons only so it will gather this electron see it is creating a bond by sharing this electrons see that's why i put in a circle two electrons stable it is sharing its electrons stable sharing its electrons table sharing its electrons table now let us talk about carbon carbon is having four electrons now it is also sharing this this this and this so one two three four five six seven eight that means eight electrons that means its octat is now complete So over here what are you observing? Here if we will see here we will see that it is sharing of electrons. It is what ma'am? It is sharing of electrons in order to in order to attain stability in order to attain stability.

Now that can be attained in the way of getting an octade complete. or the duplet complete octat complete or getting the duplet complete this can be done in such a way so now in short you know why chemical bond is created in order to complete the doctor in order to attain the electronic configuration in order to become stable quite clear this was about the covalent bond covalent what in other terms is sharing of electrons in other terms is sharing of electrons ma'am now comes the second type that is coordinate bond now comes the second type that is coordinate bond see students coordinate bond is also referred to as data bond now understand in covalent bond two atoms are sharing the electrons with each other and creating a bond but in covalent bond one single atom is sharing its electrons and you know creating a bond in this two atoms are sharing the electrons and creating a bond but in coordinate only one atom is donating electrons and sharing electrons So in coordinate only one atom is sharing its electrons and creates a bond. For example if A has electrons and B doesn't have electrons so A will share the electrons with B. So when it is sharing.

arrow will be made in such a way. That means A is sharing and A holds electrons. B does not have electrons.

A is sharing its electrons with B. Clear everybody? Also in covalent bond it arises due to difference in electronegativity.

One thing more you can add over here. Difference in electronegativity. Now you have already understood about the term electronegativity. In the previous class that is tendency to attract shared pair of electron towards itself.

for coordinate bond in depth we will understand in the upcoming classes but yes this is a quick review of what is a coordinate bond clear everyone everybody please write it down everybody please mention it write it done that's great students that's really really very good now in short if i have to say chemical bond is categorized into now this is classification classification is done as ionic covalent and also metallic bonding see metallic bonding let me tell you it occurs between occurs between what? It occurs between kernels and free electrons. Now this we will understand in depth in the upcoming classes but yes you should know it occurs between kernels and the free electrons. Now also metallic bonding is also categorized into hydrogen bond and the wonderwalls bond.

Hydrogen bond and the wonderwall force bond basically are intermolecular bonds. Okay. And the other one ionic bond, covalent bond, metallic they were interatomic bond.

When the bonds are seen between atoms that are interatomic when the bonds are seen between molecules that is the intermolecular ones. Yeah. So one by one we will understand them but yes in the upcoming sessions. Right.

So students now comes this ends our. the very first segment of ours that was discussion with regard to the chapter chemical bonding now we are coming to your chapter that is classification of elements and periodic properties so as i've already told you we are going to discuss the homework questions the most uh asked homework questions as there you may observe that one or two questions are not in the homework which i have not discussed over here because i have not seen any kind of doubt over there they were very simple questions so the questions which i felt yes you are facing an issue You know 90% homework questions are being solved over here if one or two questions are left. If you are not able to do so you can ask in the chat section as well. So starting with homework questions we will be doing NCRT in-text questions and then we will be doing the homework question and then the previous year questions. So let us start with the very first question of yours that is problem number 3.1 that is NCRT in-text question.

Now from here from this particular page we are going to start with your homework discussion. This is your homework homework discussion for your chapter that is classification of elements that is classification of elements and periodic periodic properties clear So the very first homework question is written in front of you. Let us read it. That is problem 3.1.

It says what would be the IUPSC name and the symbol for the element with atomic number 1 2 0. 1 2 0. 1 2 0. For 1 it is written as un. For 1 you write un. For 2 you will write by. For 0 you will write what? Yes.

I have already told you that what have to what you have to write. For 0, you are going to write nil everybody. For 0, you will be writing what ma'am?

Nil. Yes. For 1, it is un.

For 2, it is by. For 3, it is try in such a way, right? For 0, it is nil.

And at the last, you have to write yum. So, what it will be ma'am? It will be un, by, nil, yum. So, ma'am, this is the name for 120 atomic number and what are the symbols?

The initial letters U, B, N. So, it is U, B, N. this is the symbol everybody write this homework question down so that we can move on to the next part done with this yes everybody done done done done done that's great next question comes now problem 3.3 the element z is equals to 117 and 120 have not been discovered yet in which family group would you place these elements and also give the electronic configuration in each case so it's very simple students if i'll talk about the Group number 117, it belongs to your halogen family. To which family ma'am?

To halogen family. So it will have the same electronic configuration of the halogen family. That is going to be NH2NP7. Sorry, NH2NP5. That means 7 electrons in the autonomous shell.

so this will have the same electronic configuration as this and over here if you'll see in the halogen family fluorine chlorine bromine iodine all of that all of that stuff 117th lies in the period number seventh so the outermost electronic configuration is going to be 7s2 7p5 clear everyone write it down students fast so that i can now move on to your 120 element Okay, so family we have already told it is halogen family. Group also they are asking it is group number 17. Then our next part is about 120. See 120 basically lies under alkaline earth metals. And if I will talk about the group that is growing to be your group number 2. And if I will talk about the configuration it will have NS2. 7S2. clear outermost configuration clear everyone moving on to the next question we have uh problem 3.4 considering the atomic number in the position in the periodic table arrange the following elements in the increasing order of metallic corrector which order metallic correct right we have been provided with silicon Beryllium, magnesium, sodium and phosphorus.

Yes everybody, yes everyone. See sodium lies over here, magnesium over here. Okay and I'm just writing the order students.

Okay in order to make you understand. Then we have it is like this no? Beryllium, magnesium, sodium, magnesium over here and then we are left with potassium and silicon yes sorry phosphorus and silicon not potassium so first of all there is no way to light lithium lithium i've written for the belly beryllium sake okay yeah So we require only sodium over here.

Yeah. So this is going to be group number second. Now we require which which element?

I am going to put tick over here. We require beryllium. We require sodium.

We require magnesium. Right? Yeah. Among group 1 and group 2, these are the elements.

Now we have to tell the metallic order students. So what will be the order as per the group students? What do you feel what is going to be the order? Anybody just think about it. Just think when you're moving across the group N along the period.

See very simple thing if I have to tell you when I'm moving from top to bottom no metallic corrector will increase and when I'm moving from across a period metallic corrector decreases and non-metallic corrector increases. Okay let us talk about sulfur and silicon over here. not sulfur and silicon phosphorus and silicon again and again it comes out to other words yeah so phosphorus belongs to its family nitrogen family yeah nitrogen phosphorus and if i'll talk about your oxygen over here oxygen then we have silicon yeah no it silicon oxygen sulfur selenium tellurium polonium and if i'll talk about carbon over here for carbon we have carbon then silicon yes silicon germanium in such a way so here we require not carbon not silicon not oxygen not sulfur not selenium in this way this is the order now see when you're moving from top to bottom metallic character increase i am deleting other elements i am deleting all the other elements yeah see now we have this trend over here here see metallic character decreases that means this is going to be the order and from top to bottom it increases so this is going to be the order yeah so this is going to be the order we have total five elements this is going to be the order the highest one will be of whom and the highest one will be of sodium Then it will have a fume and then it will have a magnesium. After that what we will have?

We will have beryllium and then we will have silicon and at last it will be phosphorus. So it is sodium, magnesium, beryllium, silicon and phosphorus. If you want to write it belongs to your carbon family that means your group number 14th, it belongs to your 15th group. Clear? And if it belongs to your group number 2nd, it belongs to group number 1st.

By this way you can write it down. so clear students shall i move on to the next one done done done done done done done done great now in terms of period and group where would you locate the element with z is equals to 114 now i guess this back exercise question we have already discussed in the class yeah this we have already done with 114. now comes the questions which i have given you as a homework in the long form of periodic table all the non-metals are placed under the very first is s block p block d block f block so very simple all the non-metals are placed under the p block family now only we have seen that when we are moving across a period that means from left hand side to the right hand side my metallic character is going to metallic character is going to decrease that means non-metallic character non-metallic character will increase. So that means all the non-metals are placed under the right-hand side of the periodic table that is p-block elements.

Hence answer comes out to be option number b. Clear everyone? Shall I move on to the next question? Everybody write it down. Everybody write it down so that I can start with my next question now.

Done students? Okay here comes your next question which is which is a metalloid? P, B, S, B, B, I and Z. So students quite easy option number B is the right answer.

What is the metalloid which holds the properties of metals as well as non-metals? Clear? Simple question.

Moving on to the next one. The element with atomic number 15. 55 belongs to which block s block p block d block f block so i can write the configuration or not if you know the uh let us talk about group number one see it has atomic number one now you have to use the magic trick 2 8 8 18 18 32 so add 2 into 1 you will get 3 you add 8 into 3 you will get 11 add again 8 you will get 19 add now 18 into it you will get what 37 now add again 18 you will get what 55 so cesium basically is the element which has atomic number 55 and it belongs under the s block element so the answer comes out to be option number a as it is cesium Clear everybody. Write it down so that I can move on to the next question of ours. Done students.

That's great. Now students come which of the following alkali metals has smallest size? Now alkali metals.

What are alkali metals? It is basically hydrogen, lithium, sodium, potassium, rubidium, cesium and francium. so see when you're moving from top to bottom in a group what happens ma'am number of shells increases if number of shells are increasing atomic size will also increase ma'am if atomic size is increasing so this is going to be the order so the least one will be hydrogen is hydrogen there no lithium there no then we have sodium so answer here comes out to be option c Answer here comes out to be option number C.

Clear everyone? Smallest size. Clear? Let us see the next question now. Which of the following ionic species has largest size?

Now this is the different kind of question. Many of you will say ma'am now only we have seen top to bottom lithium will have the smallest size. See lithium students do has a smallest size but it can be hydrated.

It is heavily hydrated. It is heavily hydrated. It is heavily hydrated and if it is heavily hydrated then lithium positive ion in aqueous form will have the largest size.

It will acquire largest size if it is heavily hydrated. The smallest size will have the largest you know size in aqueous medium because it will be heavily hydrated. That means lithium aqueous will be the right answer. Hence option number D is the right answer everybody. Everybody write it down so that I can move on to the next question now.

Shall I? Done students. Okay.

Now comes chloride, iron and potassium ions are isoelectronic then. Isoelectronic refers to as the one which has same electrons. So if they have same electrons then which of the following is right? A. Their sizes are small.

B. Cl-ine is bigger than K-ine. C. K-ine is relatively bigger. D. Their sizes depend upon other cation anions.

See, if they have same number of electrons, then you always have to remember anion size will be greater than the cations one. Cations are smaller. So, anions are negatively charged. So, that means anions are, that means Cl negative is bigger than the K positive one.

So, B option is going to be the right answer. Let us see the next question. Smallest among these species are?

Very simple. Now only we have seen top to bottom number of shells increases. So, the size is going to be increasing, right? if size is increasing hydrogen will have the least smallest size so smallest among these species is hydrogen the next is it's time for the previous year questions students now we have completed basically our you know we have finished our homework session over here i hope so now your homework queries are clear now we are starting with the previous year questions the very first is the iupsc name of an element with atomic number 119 is going to be what now see this is the previous yearly asked question from for different competitive exams Starting with 119 atomic number for 1 we are going to write un again for 1 we will write un for 9 we are going to write e double n. So it is going to be un un in em em.

So this is going to be the name un un in em that means ma'am option number a is going to be the right answer. Option number A is going to be the right answer. Clear everybody? Everybody please write it down.

Done? Okay. Let us see the next question.

Next question is the electronic configuration of an element is this much. What is the atomic number of the element which is just below the above element in the periodic table? See what are the number of electrons? First of all see 1s2 2s2 2p6 3s2 3p3 that means 2 plus 2 4 4 plus 6 10 10 plus 2 12. 12 plus 3 is how much? 12 plus 3 is 15. 12 plus 3 is 15. Yes, everybody.

So, what do you feel? To which group it would lie? It is 2s2 3p3.

2s2 3p3. Which family? Which family?

Nitrogen, phosphorus. Yeah? So, oversee.

Nitrogen has an atomic number 7. If you will add 18 to it, it will become 15 p-block elements. So phosphorus, nitrogen phosphorus, then arsenic, then antimony and then bismuth. So then you are going to add what? You are going to add what?

18. If you are going to add 18, what you will get? 33. If you are going to add 18, what are you going to get? 33. That means the next element arsenic will have an atomic number 33. Simple, easy.

Shall I move on to the next question if it is done students? Yes, everyone. If it is done, can I move on to the next question of yours? Everybody write it down for once.

If the atomic number of an element is 33, it will be placed in the periodic table in what? Now only we have seen 33 element is basically, it lies under which period? 33, 1. Now only we have seen, no? It is 33 element. It lies under the P block element.

It lies under the group number 15th. Right? That means the 5th group.

Group number 15th is basically the 5th group. So, option number C is the right answer. Clear everyone?

Option number C is the right answer. 5th group or 15th group? 5th group or 15th group? Clear?

Next is? Which of the following oxides is most acidic in nature? Most acidic in nature.

Let me tell you students, BEO is most acidic in nature. Why? Because metallic character as we move from top to bottom increases.

If metallic character basically increases, that means basic character is increasing, right? So, most acidic will be BEO. Clear? Moving on to the next question now. Among the elements, calcium, magnesium, phosphorus and chlorine, the order of increasing atomic radii.

Now, this is... A kind of a question that is your homework for now. Yes, this is your first homework question for today. Your first homework question because see atomic radii hold some variations, some of the exceptions. So I want you all to try by your own as well.

So this is first homework question. Among the elements calcium, magnesium, phosphorus and chlorine, the order of increasing atomic radii is what? A option, magnesium have the least, then calcium, chlorine, phosphorus. B is chlorine, phosphorus, magnesium, calcium. C is phosphorus, chlorine, calcium, magnesium.

D is calcium, magnesium, phosphorus and chlorine. Moving on to the next question. Which of the following has the largest size? Very simple.

Anion will have the largest then the parent atom then will be the cation. So anion that means Na negative then it will be Na and at last it will be cation, Na positive. So this is going to be the order.

Which has the largest radii? Option number C will have the largest radii. Next.

Which of the following has maximum electron affinity? Yes students, now we very well know fluorine, chlorine, bromine, iodine electron affinity basically. When we move down the group, what happens to that? It is going to decrease because size increasing but there is an exception, chlorine will have the highest electron affinity. So option number D among the following is going to be the right answer.

Yes, so yes students here we are going to end our today's class. I hope so your today's class was helpful for you. You were able to solve questions, you were able to understand about chemical bonding but now in the next lecture we are going to do a lot of structure based questions, a lot of structure based concepts. So be prepared for that session and yes do revise your previous chapter because revision is really really very essential if you are preparing for any competitive exam. Now students we shall meet you in the next class.

Till then keep smiling, keep learning. Thank you so much my dear students. Take care. Bye bye.

Thank you.

Transcript for:Understanding Chemical Bonding Concepts

Transcript for:
Understanding Chemical Bonding Concepts