hello everyone welcome to Chapter five in this chapter we will discuss molecules through compound learning objectives this chapter is divided into three parts in Part A we will discuss chemical formulas and ionic compound in Part B we will discuss molecular compound and we will close the Part C where we will discuss acids and formula much chemical formulas a chemical formula is a way of expressing information about the atoms in a particular compound more specifically a chemical formula indicates the elements present in the compound and the relative number of atoms of each for example here is a compound water molecular compound it contains a total of three atoms two hydrogen's one oxygen another one hydrogen peroxide it contains a total of four atoms two hydrogen's two oxygen atoms carbon calcium and sorry hydride don't worry about the name we are going to learn the name later on it contains three atoms it's unit contains one calcium atom and two hydrogen atoms barium nitrate again don't worry about the name it's unit contains one bottle and two of these units that means two nitrogen atoms and six oxygen atoms again let me say it again from the beginning each unit contains one barium atom and two of these units each unit contains one hydrogen two oxygens so the two units contain two nitrogens and six oxygens the resolution why I have divided these examples here we have one type of compounds and here we have a different type of compound so we are going to say later on these are molecular compounds this array only compounds pure substances pure substances are divided into elements and compound elements it's a substance that cannot be chemical broken down to simpler substances for example helium oxygen iron hydrogen sodium calcium and etc compounds the air substances that are composed of two or more elements for example in the molecule of water we have both oxygen and hydrogen and the ratio is 1 to 2 table salt contains sodium and chloride and etc chlorine our element the elements can further be divided into atomic and molecular element's atomic they exist with single atom as the basic unit need helium argon and etc molecular elements exist with two or more atoms of the element bonded together for example can you see here the building unit at the case of hydrogen is aged to two atoms have come together in order to give us the element the same for nitrogen the same for oxygen the same for chlorine the same for bromine two atoms are coming together in order to give us the unit the pure substance the element compounds are divided into molecular and ionic molecular are those that are composed of two or more covalently linked nonmetals well our unit are those composed ionic compounds are those composed of a cation and an anion all together electrostatically however we are going to further discuss molecular and ionic compound types of chemical compounds or if you want types of chemical bonds remember this is the periodic table that we discussed in chapter 4 we said about this side of the periodic table the blue region we have the metals and here we have the yellow region we have the nonmetals including the hydrogen here on the they are gonna line the green are the metalloids however we will not discuss at this point the metalloids we will be focusing on the metals and the nonmetals so when an element from here a metal it's coming together with an element from here nonmetal in order to form a compound then that compound is an ionic compound and the bond the interaction between the tube is an ionic interaction an ionic bond now when two elements from here two nonmetals are coming together then we are forming and molecular or if you want a covalent compound there are cases where two metals are coming together then at this case we are forming a metallic bond and metallic compound and that's not something we will discuss who will is included in the material of this course so we have a only compound and we have molecular compounds also we have metallic red Google not discuss in part a will focus on ionic compounds we will discuss the definition of ionic compounds what we know already we are going to see a couple of examples we are going to write we are going to learn how to write any compound and then we are going to learn how to name my own compound i only compound consists of a positively charged and the negatively charged ions so the positively charged species may be metal or a complex since it has a positive charge is called cation the negative charge can be a nonmetal or a polyatomic complex that it's called an iron again are you only compounds have a positively charged and a negatively charged are you on the positively charged can be metal or a complex since it has a positive charge it's called cation the negatively charged species I it can be a nonmetal or a complex they are called anions since they have negative charge here we have something that it has a negative charge and something that it has sorry something that has a positive charge and something that has a negative charge so they attract each other the interaction between the two is of electrostatic nature it's called an ionic bond the ionic bonds tend to be strong ionic compounds they're high melting points and high boiling points to be honest with you I only compounds do not have boiling points they we further we destroy before we reach the boiling point of the compound I only components are solid at room temperature ionic formulas the ionic formulas consist of something that it has a positive charge and something that it has a negative charge however the whole compound is neutral so the church needs to be balanced since the neutral the church needs to be balanced what does it mean that the total positive charge needs to be equal to the total negative charge when we write an ionic compound first we write the metal and then we the nonmetal or if you want first we write the species that has positive charge and then we write a species that has the negative charge let's see a couple of examples so do if you look at the periodic table and I waste that as you are watching the lecture you have the periodic table next to you the sodium tense is a metal and it tends to lose electrons while the chlorine is a nonmetal it's at the column seven a and D tends to gain electrons so whether you're going to come close to each other the sodium is going to lose one electron and is going to be converted into sodium plus and the chlorine is gain one electron it's at the 70 right it is going to be converted into CL minus now the atoms the sodium atom and a chlorine atom are not stable they are stable however at this for sodium plus chlorine minus since the sodium has a positive charge we say that this is the sodium cation this has a negative charge this is the chlorine anion we call it actually fluoride so cation and i these two attract each other and they are stable and they come close to each other that's another one magnesium has the tendon is a matter has a tendency to lose electrons right how many look at the periodic table it's at the column two way so it has the tendency to lose one two electrons and give the magnesium two-plus while a chlorine atom has the tendency to gain one electron and be converted into CL minus so one electron from the magnesium is going to go to the one chlorine and the other electron from the magnesium is going to go to the other chlorine magnesium with two plus is going to attract chlorine with one - and another one chlorine with another one - so the whole thing the magnesium with two chlorines isn't neutral writing and your compounds remember what we said at the beginning the simplest ionic compounds have in the metal consist of a metal and a nonmetal first we write the metal and we write a nonmetal consider the case of volume and chlorine if you look at the periodic table the barium exists us volume 2 plus and the chlorine exists with negative 1 charge in order to write the compound basically we are crossing the charges we are going to put the 2 here and the 1 here you don't need to put the 1 here here is the compound its body which is going to need two chlorine atoms let's see a couple of more examples calcium is coming together with bromine if you look at the periodic table elements is are they to a column of the periodic table so charge 2 plus well bromine is at the 7a so charge 1 - when I will write the formula we'll put the 2 here and the 1 here however I don't need to write the 1 at all here's the formula let's say this one try to do it by yourself there's something tricky about this the sodium is the metal so I'm going to write it first the bromine is the nonmetal let's predict the charges if you look at the periodic table sodium 1a so 1 plus bromine 7a so 1 minus 1 here 1 here I don't write anything the next one try to do it by yourself dal-su to a column of the periodic table right so to blast charge sulfur six a so the charge is going to be two - when it comes to a you only compounds we write the simplest ratio so despite the fact that I'm supposed to write here 2 & 2 2 & 2 I will not write anything the simplest ratio is 1 to 1 here we go next one oxygen and aluminum which one are you going to write first the metal what's the charge for the metal who will say soon what the church prabha nonmetal here they are the charge for the aluminum strip to us given the be a luminary minim is at the 3 a column of the periodic table and then the charge for the oxygen is 2 - given that it is at the column 6 a compound I'm going to write a 3 here and I'm going to write a 2 here next time try to write it by yourself what's the matter with a non-metal what are your church is here it is yes sodium is the meta nitrogen is a nonmetal charges last one minus three so here we're going to have a three at the case of the sodium we are going to have a subscript three while at the case of the nitrogen we are going to have a subscript one or the donor actually we don't write anything here's the compound naming ion the compounds first of all we are going to see only compounds with two elements these are called binary compounds when we have naming binary compounds first we name the cation aluminum for example calcium sodium and etc and then we name the anion however at the end we are going to have an ID chloride bromide oxide sulfide nitride and etc transition elements do you remember when we were discussing the periodic table we said that here we have the nonmetals and here we have the metals at this region we have the main metals as well as here and here in the middle we have the transition metals all the transition elements main elements tend to have one and only charge transition elements have multiple charges and it's difficult to predict from the periodic table at least this is not the scope of this course so when it comes to the transition elements we need to give the charge of the element in the compound given that the transition elements most of them have multiple charges let's see an example here I don't chloride the iron has plus 2 or plus 3 in this particular example the iron has 2 plus charge and we can see it from the 2 that we have here as a subscript after the chloride so the name for that even that the iron is a transition element is iron 2 chloride so for us if we have an element from the main groups we do not need to specify the charge if we have an element from the transition elements from the transition metals then we need to specify the charge there are exceptions but we will not go there so let's say the compound that we have here this one can you tell what's the cation what's the in iron sodium and chloride last one - one you can tell from the periodic table and what's the name sodium chlorine it has a negative charge so it's chloride sodium chloride next one with the cation well potassium potassium is a big one a column of the periodic table so the charge is plus one and then we have so far what's the charge six a column of the periodic table so it's two - here are they the cation and the anion here are the ions the name potassium sulfide next one magnesium oxygen charges two plus two minus here there but why don't we have subscripts well we said that we are reporting the lowest ratio right - here - here our consult here we go magnesium oxide is then named magnesium oxide ions potassium - plus I'm sorry calcium that's what I meant to say calcium and are you dying what's the charge one - it's a seven eight column of the periodic table names the name for the compound potassium iodide next one here aluminum charged three plus sulphur charged to - we can see them from the periodic table we can find the charges from the periodic table right here they are named aluminum sulfide this one iron what's the charge well given that the sulfur has to - that has to be 2 plus this is a transition element we cannot predict the church unless we know the entire from the in iron we figure out that the charge for the Iran is 2 plus so the name since this is a transition element it has multiple charges it's iron - sulfide let's say problem here we have to give the charges for the cation and be an iron for all the compounds that we have here and after that we have to name the compound notice for that all the metals that we have here the cations that we have here are transition elements transition metals I would like you to pause the presentation try to answer the the problem and then come back and compare your answers with the answers that would sit together welcome back let's say the first time when we have to predict something like very essential we don't know the transition element we will be starting from the time sorry for the Ania for the nonmetal this is a chloride this is a chlorine so the church is going to be 1 - given that we have it - here the charge for the ion is going to be 2 + also we can we can solve for the charge of the cation litical we are going to do the whole complex is neutral so if we put as X the charge of the iron we have X + twice - wah where - 1 is the charts for the entire is equal to what 0 so this equals -2 right so X minus 2 is equal to 0 and from here I'm going to solve for X X is equal to plus 2 the name now the name since this is a transition element is going to be iron tube fluoride here is the name let's say the next one bromide what's the charge 1 - it's at the column 7a right and then the charge for the ion is going to be 3 plus the name for the compound iron 3 bromide what's the in iron here oxygen what is the church for oxygen 2 - we know that from the its position in the periodic table and then what's the charge for base for copper 1 plus well since this since the charge for the oxygen is 2 minus the 2 minus goes here that means the charge for this has to be 1 plus let's see how we can show for that if you find it kind of difficult to to see it by looking just at the compound so if we put X the charge on the copper we have twice X plus minus 2 is equal to 0 so from here we have so from here we have twice X minus 2 is equal to 0 let's bring that - but the other side is going to become plus 2 so twice X is equal plus 2 so X is equal to plus 1 so what's the name for these copper one bauxite here's the name let's see the next one what's the Ania oxygen with what's the charge - - we know that from the periodic table right here we go notice that despite the fact that oxygen has a minus 2 charge here we do not have a subscript so what do you think that the charge on the cover is going to be 2 plus and then the name topper - oxide copper Q oxide copper is a transition element right next one nitrogen is the anion the nonmetal so what is the charge on the nitrogen we know that from the periodic table 3 - so given that we did not have any subscripts what's the charge for the manganese 3 class and then the name of the compound is manganese 3 nitride next time so for what's the charge - - and then given that we have it two and two three besides a sharp Spears what's the charge on the chromium 3 plus we see it from here so the name of the compound is going to be chromium 3 sulfide next one here we go phosphorus is the nonmetal so what's the charge on the phosphorus 3 - we know that from the periodic table it's at the column by a and then given that we have subscripts 3 & 2 what's the charge of the chromium 2 plus so also you can set up your equation write your equation is going to be 3 times X + twice - 3 is equal to 0 now what's the name for this chromium K for spite here we go another one exercise for us we have to complete the table by giving either the formula or the name for the following compound they are ionic compounds I would like to ask you for another one time to post a presentation and try to answer the program by yourself welcome back so let's see the first part what's the name for this aluminium from out the aluminium is a main element next time what's the name like an issue clora main element next one sodium sulfide the sodium is a main element next one calcium and nitrite well the calcium has charged to plus it's a main element we can see that from the periodic table nitride three - so what I need to do I will need to have it to subscript for my nitrogen and the three as a subscript for the calcium here's the compound next one palsu sulfide calcium is a main element I don't need to specify the charge next one aluminum and sulfide so for aluminum three plus so for two - I know from the periodic table the only thing that I need to do is cross the churches here is the compound next one ion and phosphorus I reduce the transition elements so I need to figure out the charge what is the charge for the phosphorus 3 - given that they do not have such scripts that means that the charge for the iron is 3 + here we go so the name is going to be what I know three phosphide last one calcium and oxygen both of them might main elements see the charges of Q plus to minus so I'm going to put the simplest pressure and it's going to be face now so far we saw how would we name binary ionic compounds that means we had one element a second iron and one element is in denial what about if we have polyatomic ions what about if we have polyatomic complexes as anions and cations well as far as the cations are concerned the only only atomic cation that we are going to see it's going to be a Mondial ammonium has nitrogen four hydrogens and the positive charge you need to memorize it as it is however as far as the in I am Cisco are concerned we are going to see several of those this is the cyanide you need to memorize it acetate carbon nitrogen with a negative charge very common hydroxide oxygen hydrogen with one minus charge and then ammonium bromide ammonium has plus one charge bromide has minus one charge so no subscript the subscript that we have for the for the hydrogen here the four is because of the ammonium ammonium hydroxide plus one minus one we don't need anything else calcium hydroxide can you see the calcium has two blasts hurts the hydroxide has minus one so we need to put in a parenthesis the hydroxide and to put outside subscript two because of the charge that we have the culture so in the unit of the calcium hydroxide we have one calcium ion and took hydroxides each hydroxide has one oxygen that means a total of 2 and each hydroxide has one hydrogen that means a total of 2 hydrogen atoms in the calcium hydroxide ammonium sulfide ammonia plus one sulfide minus 2 so we need to put in the parenthesis the ammonium and we need to put outside to outside now in the ammonium sulfide unit how many nitrogen atoms do we have yes - and how many hydrogen's yes twice for now how many ammonium cations do we have in the ammonium sulfide - that's why we have that the two outside of the parenthesis Iram three hydroxide the charge for the iron is three plus for the hydroxide is one minus so we need to put a hydroxide in parentheses and put three outside let's see now oxy containing polyatomic anions in other words we are going to see polyatomic complexes that contain oxygen and they are negatively charged we are going to see a series of cations where the name has an ending eighty later on we are going to see another one set with I T at the end don't worry about the idea at the moment let's see the aides the polyatomic anions that contain oxygen the oxygen taining polyatomic anions with and ending of 8 we are going to see one organic and several in organics we will see the formal and the name the first one ch3co and the negative charge you can see it like a vase or like this the name is acetate you have to memorize it you have to memorize the name and there the formula nitrate nitrogen with three oxygens and the negative charge sulfate so for with four oxygens and two minor charge phosphate four oxygens the three minus charge carbonate three oxygens and the two minus charge you need to memorize them there is no other way and then see the halogens chlorine bromine iodine they are all hi I'm sorry they are all halogens they are at the column 7a of the periodic table all of them have one halogen three oxygens and one minus charge and we have chlorate bromate are you did similarly we have the flow rate as well is not included here not p8 need to be memorized there is no other way around these are the hallways right because they are coming from the college we can take each one of these and remove one oxygen leave the charts as it is so here we are going to help and note 2 negative charge so 3 to negative charge po3 3 negative charge co2 2 minus CL o 2 1 minus charge here they are and then the name is that of nitrate is going to be nitride instead of sulfate it's going to be so far it is that the phosphate is going to be forced by instead of carbonate is going the Carbonite Carbonite doesn't exist however for me it's a good example at this point in order to be able to work with you on this on this list that we have here here are the hollow eyes so you have to memorize this and then the remember that you need to remove one oxygen leave the charger cities and then you're good that's how we're going from the aides to the eyes but there is no other way other than memorizing ways I repeat it again you have to memorize the aides so let's say cup of examples here actually what I want from you is to pause your the presentation and try to write either the name over the formal of the a on the compound and then come back welcome back let's say the first part sodium can you to remember this one here it's nitrate charges plus one minus one this is a main element so we don't need to worry about the charged sodium nitrate next one sodium nitrite nitrate is going to be like the nitrate but why not sterilized here it is can you see here we have two oxygens not free do we need subscripts no window we don't this is the formula next one copper one sulfate they let us know the charge format copper because it's a transition element so we are going to have this is the cation and this is the Anaya we are going to press charges the copper is going to have it a two subscript the sulfate is not going to have anything aluminum sulfide aluminum al three plus with no from the periodic table sulphide is going to be the same as the sulfate however it's going to have one oxygen lysis also the sulfate is so4 to - hey remember that so the sulphide is so3 - here it is three plus two - I will cross my charges any member to put a parenthesis here next one I wrote to sulfate well I don't hear sulfate I remember that 2+2 - oi delete subscription aluminium this is a carbonate with three oxygens aluminium has a three plus charge carbonate has a 2 minus charge aluminium carbonate the next one sodium sulfate sodium na with one plus charge so theta I remember that po4 3 - so I will need to put three as a subscript here for the phosphate and not continued anything thousand chloride calcium is a main element so that straightforward chloride it's going to be like a chlorate clo3 1 - but then I need to remove one oxygen see I remove the oxygen is CL or - 1 - now 2 + 1 - crossing charges at this point we'll have finished with chapter 5 part a we spoke about ionic compound basically we give the definition at a couple of examples we discuss how we can write them and how we can name them we spoke about simple ionic compounds that they consist of a metal and a nonmetal and then we spoke about polyatomic complexes as far as the cations are concerned we have only one a monument attire as far as the negatively charged polyatomic anions are concerned then we have several and you need to memorize some of them ok I will see you in Part B with molecular or covalent compounds thank you