Chemical bonding part 15

Hinzugefügt: 2026-05-18

[00:00:00]now coming to the postulates now here i'll be using three that is alphabets a b and l now what is that you see a for the central atom b for the surrounding atom means around the central atom the other atoms which are there that is the surrounding atoms and l for the lone pair of electrons all right you can say b also for the bond pair also we can also say this is bond bit all right so a is a central line b is the surrounding atom or the bond pair and l is the lone pair of electrons you must be knowing what is lone pair lone pair means a pair of electrons which does not participate in bond formation after the central atom has attained the octet structure once the central atom attains the octet structure you will find a pair of electrons some pair of electron either it may be one pair two pair three pair whatever it is some pair of electrons is left which does not participate in bond formation that is called as a lone pair i can immediately give you one example see here this is the structure of ah sorry this is the structure of water molecule now once we learn vsapr we need not draw as i was drawing linear molecule we will be drawing this so you can see oxygen is having oxygen should have how many eight electrons and hydrogen should have two electrons hydrogen duplets c duplex one two counted see one two electrons here hydrogen is duplicate here in this hydrogen also one two two plate all right so as a result oxygen is having one two three four four electrons now five six seven eight see here i think you can see very clearly so in this way you can see here that is this two pair of electron this is one pair this is another pair these two pair of electron participates in bond formation so this is known as bond pair this is called as bond pair bond pair of electrons all right now this two pair of electrons see after retaining the octet structure now oxygen is octet how disrupted one two three four five six seven eight so okay so after oxygen has attained octet structure you can see very clearly two pair of electron does not participate in bond formation which is on a smart lone pair of electrons that is what i am saying here what is lone pair lone pair means a pair of electrons which does not participate in bond formation after the central atom this is central atom it is very important to say that after the central atoms attain the octet structure and always you will find the lone pair for the central atom only not for the surrounding atoms you will find the lone pairs for the central atom only not for the surrounding atoms because lone pair is a term which is used only for the central atom not for the surrounding atoms suppose in the surrounding enzyme let us say some lone pair is some pair of electron is there which does not participate in bond formation but that is not considered as a lone pair for example suppose if i say the molecule of sulphuric acid if i say the molecule of sulfuric acid we can say that okay so here you can see is that that s is the central atom so here whatever the pair of electron is left it does not participate in bond formation this is two are coordinate bonds okay so it does not participate in bond formation that is called as a lone pair because here you will find pair of electron which does not participate in bond formation but that is not the lone pair here also you will find it out that is not the lone pair this is not the lone pair mind it this is not the lone pair this is a central atom here sulphur is a central atom here if any pair of electron is left which is not participating in bond formation that is called as a lone pair i hope you got it now this is not the lone pair in this example in sulfuric acid oxygen is not oxygen is not the central atom it's the surrounding atom here the central atom is sulphur so you will say say here low pair lone pair no absolutely wrong for this molecule this is not the lone pair for this molecule i am saying that for this molecule for sulfury cancer here oxygen is not the lone pair understood i hope you got it this now so hence i will tell you the postulates now and i'll explain it also to you the postulates one by one the unpaired electrons in the valence shell of the central atom forms bond pairs with the unpaired electrons of the surrounding atoms while the paired electrons remains as lone pairs what i said is the unpair the first point the unpaired electrons in the valence shell of central atom so central atom can have but you can say lone pair as well as what you can say bonding so what is saying is that the unpaired electrons in the let me not write this so this is your unpaired electron this is your paired electron as you can see very clearly this is unpaired and this is your period so unpaired electrons i am pointing it out the unpaired electrons in the valence shell this is your valence shell let us say outermost shell of a all right forms bond phase with the unpaid electrons of the surrounding atoms let us say surrounding atom is b already i have told you so with the unpaired electrons of the surrounding atoms it forms bond pair so b is having an unpaired electron so he is having an unpaired electron so they undergo the form what is that bond pairs so again i repeat the unpaired electrons of the but against the central atom forms bond pairs with the unpaired electrons of the surrounding atoms all right while the paired electron let us say only one pair is there only one player let us see it forms lone pairs when the paired electrons remain as lone pairs fine the first point is clear now coming to the second point second point is such that lone pair and the bond plates they are similarly charged definitely this is also made up of electron this is also made up of electron lone pair is made up of two electrons the bond pair is also made up of two electrons now one bond pair is having two electrons it can be from definitely different atom or samada whatever it is clear so being similarly charged they tend to repel one another differently they will literally because they are similarly charged third point is that third point all right the second point understood being similarly charged they will tend to repel another definitely because they are made up of electrons whether it is a bond they are alone now third point is that so as to have minimum repulsion and maximum stability they will go far apart from one another suppose if these lone pairs on the bond periods they are closer to each other or this bond parent bond pair they are closer to each other being similarly charged all right as they're repelling one another so as to have minimum repulsion listen carefully so as to have minimum repulsion and maximum stability they will go far apart from another you will not take them far apart they will itself arrange in that manner try to understand this point we are not arranging them they will itself arrange in such a manner so that the repulsion will be minimum all right clear so the electron pairs the next point is that the fourth pen is that the electron pairs around the central atoms set themselves in such a manner so that they have minimum repulsion and maximum stability they set themselves electron pair they arranged themselves in such a manner i told you before coming to the postulates they arrange themselves in such a manner because they are directional this is a colon bond it is directional i am not talking about electro valine bond here it is directional bond so b what you can say is that so has to have minimum repulsion on it they will arrange themselves in such a manner they will set themselves in such a manner so that they will have minimum repulsion and maximum stability so when they will set themselves they will set themselves in what in a particular that is something but angle in a particular bond length they will have it they will have a particular bond line they will have a particular bond angle all right hence they will have a definite geometry a definite structure we can say that got it so that the force of repulsion among them will be minimum all right this is the most important point they will arrange themselves itself arrange themselves in such a manner got it now next is the force of repulsion among the bond payers and the lone pairs is not the same but it is not the same among the bond paids and the loan base loan pay pair the last point this is the fourth point i have discussed with you now fifth point that i said you the fourth repulsion among the bond paints and notepads is not the same lone pair loan pay repulsion is greater always greater than bond pair bond pair repulsion why because in lone pair what you find is that let us say that having two pair of electrons let us i am having two pair of electrons okay let me rub this i am having two pair of electrons here you are having two bond psa let us say two lone pairs here so lone pair means what i said this pair of electrons do not participate in bond formation that means they have a complete electron cloud all right a full electron cloud so when these two electron cloud will come closer to each other apply the common sense they will not repel one another definitely they will repel one another all right but in case of bond pairs what happens is that they overlap in this particular way this electron and this electron they overlap in this particular manner so the electron cloud tends to shorten itself but here there is no question of overlapping because here they do not participate in bond formation so the electron cloud is of the normal size product it is whatever it is the same size we can say that the normal size it is the actual size but here the size is smaller why because when they come closer to each other the sharing of electron takes place due to which the electron clouds tends to shorten shorten themselves because what i said attraction is taking place followed and here what is happening repulsion is going to take place so due to repulsion they will go far apart from one another this it will shift here and this will shift here they will go far apart from another but here also repulsion is going to take place but here the electron cloud is shorter it's smaller so the here of the repulsion definitely will be smaller here as the electron cloud is bigger the repulsion will be also bigger will be larger so hence for that particular purpose lone pair lone pair function is always greater than bond pair bond pair pulse do you get it this is a smaller electron cloud in case of bond pair but in lone pair it's a larger electron drop because already i said this does not participate in bond formation it is the actual size we consider clear so as a result when they come closer the two electron clouds which is a bigger size definitely the repulsion will be more but here the repulsion is less so hence always lone pair lone pair repulsion is greater than bond pair bond pair repulsion now what is lone pair bond pair repulsion we we have talked about this and this we have talked about this and this what about this and this or this and this lone pair and bond pair don't tear in bond pair what about this it lies in midway it lies in between it lies in between lone pair lone pair and bond pair bond pair so hence ultimately what we can say that is ultimately we can say that let me make this one as bond pair and here let me write as loan pay so what we can say loan paid loan pay repulsion is greater than loan paid bond pair repulsion is better than bond pair bond pair function because here we are having two lone pairs definitely greater than two bond pairs which will be smaller but here one lone pair and one bond pair definitely due to the presence of one lone pair what will happen is that the repulsion is slightly more than this then broadway bond pair so hence it lies in between for that particular purpose so hence lone pair lone pair repulsion is better than normal bond pair repulsion is greater than bond pair bond variable i hope it is clear to you so these are the postulates the first point is that that when the atoms they come closer all right there is this one as you can see this central atom which is surrounded by the surrounding atoms so first they found bond plates with the unpaired electrons and the paired electrons remain as lone pairs you can see that now being similarly charged what if this is not lone pair or it don't get confused so being similarly charged the lone pairs and the boundaries whatever it is they tend to repel another because they are same charges electrons now to have minimum what you can say repulsion and maximum stability they will go far apart from another definitely next is they will arrange themselves so as to have minimum repulsion maximum stability they will arrange themselves in such a manner so that the force of repulsion among them is minimum they will set themselves they will arrange themselves now next of course your repulsion is not the same the lone pair lone pair is better than lone pair bond pair is better than body weight bond pair repulsion so these are the five points or the postulates of the vsapr theory next i will tell you what are the applications of this particular theory and what will come to know about it about the shape of the market okay thank you