 So next one the second compound you write down here that is oxide oxide formation write down the elements of group 15 the elements of group 15 forms forms three types of oxide forms three types of oxides okay the first type we have that is tri oxides okay so it can form x2 O3 types of oxides it can also form x2 O4 it can also form x2 O5 these three types of oxides forms okay so with x2 O3 the oxides that we have for nitrogen is N2O3 phosphorus O3 and bi2 O3 the other oxides forms similarly for x2 O4 it is N2O4 P2O4 A S2O4 SB2O4 and bi2O4 and the last one we have here P2O5 A S2O5 SB2O5 and bi2O5 three types of oxides forms okay now the acidic nature of these oxides is important okay acidic nature of these oxides for the oxides of same element like nitrogen can form N2O3 N2O4 N2O5 so if you have to compare the acidic strength of of the oxides of same element like N2O3 O4 O5 P2O3 P2O4 P2O5 so acidic nature of the oxides of same element increases as percent is oxygen character increase basically what you have to keep in mind and it is only for oxides of same element okay number of oxygen atom more acidic nature will be more okay so N2O3 N2O4 N2O5 may N2O5 acidic nature maximum right so that is why as you go this way of these oxides acidic nature increases okay acidic nature increases okay next you write down the acidic nature for a particular type of oxides the acidic nature for a particular type of oxides decreases decreases as we go down the group okay so for N2O3 P2O3 A S2O3 SB2O3 and all if I go this way down the group for a particular type of oxides okay so if you go this way down the group for a particular type of oxides which is trihalite tetra trioxide tetroxide pentoxide the acidic nature decreases acidity decreases tendency to accept electron is less because electronegativity is less and side is also more okay so for a particular type of oxide down the group if you go acidic behavior decreases and for the oxides of same element as percentage oxygen character increases acidity increases okay there are some fact you should know about these oxides because this is important for nitrogen oxide it forms various different different types of oxide I'll write down the order of acidity of nitrogen oxide write down acidity of nitrogen oxides it is minimum for N2O and then we have N O after this we have N2O3 N2O4 N2O5 sorry this way no N2O5 this is the order we have okay the A S2O3 and SB2O3 A S2 and SB2O3 they exist in dimer form okay write down A S2O3 and SB2O3 exist in dimer form like A S4O6 dimer of A S2O3 SB4O6 dimer of SB2O3 okay so these oxides are amphoteric in nature that also you write down this is amphoteric a question they ask in exam which of these are amphoteric oxides amphoteric oxides okay BI2O3 is a basic oxide so basic character of these oxides increases down the group that's the same thing acidity character increases so basic the character decreases so basic character increases just reverse okay but you must keep this in mind that A S2O3 SB2O3 exist in a dimer form and they are amphoteric oxides okay phosphorus oxides it is important to know that structure of phosphorus oxide I'll draw the structure here write down structure of P4O6 P4O6 is what it is a dimer of P2O3 okay and P4O10 P4O6 P4O8 P4O10 important is P4O6 and P4O10 the structure here is all the phosphorus atom sir so why isn't bismuth more basic than nitrogen what we have discussed so you said it has more electron density no no tea oxides of any type whether it's tripe tetra or penta okay down the group if you are going think acidic nature is what acidic nature is decreasing why because electronegativity is decreasing tendency to accept electron is less nitrogen to accept electron maximum no okay so Lewis acid of these oxides behavior decreases down the group so when acidity decreases what we can say basically increases that's why you can also say down the group as you go basic character will be more okay sir got it yeah now the structure of this P4O6 see in all these oxides phosphorus atoms are joined together by this thing by oxygen okay between two phosphorus atom one oxygen is present so you see here suppose we I have drawn one phosphorus here another one here and one here all these phosphorus atom are joined together by one oxygen like this this is the first thing you should know how many oxygen four how many we have six so the other two phosphorus like this it is connected with the two oxygen this way this is P4O6 clear between two phosphorus atom one oxygen present can you tell me how many lone pair and bond pair of electrons are there or how many sigma bond and how many lone pair phosphorus atom how many lone pair four phosphorus when phosphorus attached with three bonds how many lone pair one and this three as one ps3 as one so each phosphorus atom you see it has attached with three bonds correct each phosphorus atom there is one lone pair present this is one thing you also we have one lone pair you also we have one lone pair so phosphorus has one lone pair each oxygen atom has two lone pair so if they ask you how many total lone pairs are present okay you have to add all these okay if they ask you how many lone pairs present on the phosphorus atom then it will be four okay so this question they ask in the exam in P4O6 how many lone pairs are present on phosphorus how many total lone pairs are there what is the sum of lone pair of electrons present on phosphorus and sigma bond okay all these things if you know the structure you can find it out okay so this is P4O6 P4O10 is what these lone pair when it is donated to the oxygen atom right so you'll get P4O10 so the structure is let me draw the structure I'll explain that it is P4O6 here we have same thing all the phosphorus atom are joined together with oxygen this way oxygen this way and when this lone pair is donated to oxygen you'll get a coordinate bond here O coordinate bond here O so this is P4O8 you see two phosphorus atom attached with oxygen like so it is P4O8 continuous if you continue this one oxygen here one oxygen here it gives you P4O10 okay P4O10 where these bonds are coordinate bonds so how many coordinate bonds are there if the question is there are four coordinate bonds understood okay now one more thing is important here that in some book all of you have drawn this structure tell me guys yes in some book what happened in some book the structure is this let me just fix it this is oxygen oxygen in some book what happens instead of this coordinate in this this like this arrow they draw the structure this way just I'll remove this and they have given phosphorus with a double bond oxygen phosphorus with a double bond oxygen phosphorus with a double bond oxygen and phosphorus with a double bond oxygen okay so this is written in the book this double bond but this is not the uh we we don't consider this a double bond this is the coordinate one also for the third elements of third period okay for elements of third period third period elements the coordinate bond is represented by the coordinate bond is preferably represented by represented by like this double bond so don't get confused with this in the book if you see a bond written like this these are coordinate bond only not a double bond okay so keep that in mind because coordinate bond we usually consider as a covalent bonds type of covalent bond only okay so this p double bond o also a coordinate bond not a double bond you must keep that in mind okay so they have asked questions on these two structures many times in the exam they may ask you how many coordinates bonds are there they may ask you regarding lone pair they may ask you regarding sigma electrons or sigma bond present okay so the structure you must remember