 Hello, yeah, can you hear me? Yeah, okay. So we'll do some examples on this VSEPR theory find out the Structure of these molecules or ions. So the first one is I o 3 F2 minus I o 2 f 2 minus E o 2 x e f 4 x e f 2 I cl 3 and o 3 minus and o 2 minus Done finished If you know the bond pair and lone pair you can find out the shape. No, yes so you see this First of all, we'll find out the valence electron. So valence electron for this one is seven for iodine seven for fluorine so seven into three Plus six into three Plus one because one negative charge is there 21 plus 1 22 plus 18 that is 40 electrons we have so we can say five bond pair and Zero lone pair here. So five bond pair and zero lone pair. The structure is TBB Retrohydel sorry geometry and shape is trigonal bipyramidal Okay, here if you see the valence electron Seven plus 21 plus one 22 22 plus 12 that is 34. Is it 34 34, right? So 34 divided by 8 So we have four bond pair and one lone pair geometry if you see Geometry is TBP trigonal bipyramidal. I shape is what Shape is here seesaw See saw the same shape is if you look at the you know geometry here. So what we do we draw a triangle Just to understand the shape we draw a triangle. It's not like the bonding is there just to understand it, right? And we have suppose One atom present over here That is I Okay, one lone pair will be at this position any one of this three I'll place it here and then to fluorine and To oxygen if you look at this this looks like a seesaw Geometry, okay. One more thing is important. Yeah, I'll just explain it here only in Trivonal bipyramidal geometry There are two types of bond length in tribunal bipyram. Okay This bond this bond is the axial bond right down here This two bond if I have two bond we have this is This is axial bond and this three bond one two and three these are equatorial Equatorial bond We have two different bond lengths all suppose the axial bond has bond length L1 Equatorial has L2 so the bond length of axial bond L1 is greater than L2 this you must take care of The bond angle here you see between this bond and the plane of the triangle this bond angle is 90 degree This bond angle is 120 This is 120 It's a plane of the triangle and this bond angle between this bond and this plane here plane of the triangle It is 90 degree Two different bond angle we also have here. So if you have one lone pair Yes, if you have one lone pair it will place over here If you have two lone pair another corner of the triangle three lone pair another corner of the triangle, right? So this position will place the electron because the bond angle is 120 and here we have lesser repulsion Okay, this you must take care of for TVP diagonal bipyramidal. You can't say it is a Seesaw Suppose we have a line this one line is coming towards me This part is coming towards me and this part is going towards you into the plane of the screen, right? So this is the You can see here. This particular thing is placed So this looks like a Seesaw this part is nothing but this bond Then we have this line the bond angle you are talking about Now here it see ideally this is the ideal thing. I'm talking about. Okay, this 120 is for ideal when there is no lone pair I should not place a lone pair over here. This is for the ideal thing. I'm talking when there is no lone pair Yeah, this angle is lesser than 120 if there is no one pair present then this angle is lesser than 120 Okay, Xeo2 the number of valence electron you see for Xeo2 8 plus 2 into 6 that is 20 Right, so we have two bond pair and two lone pair Right, so it is geometry is tetrahedral Shape is what is V shape? We also call it as bent shape or we also call it as angular all three are same thing Xeo4 valence electron 8 plus 7 into 4 that is 36 So four bond pair and two lone pair geometry is what? octahedral square bipyramid shape is Square planar next one Xeo2 valence electron is 8 plus 14 22 So we have a two bond pair and three lone pair See the bond pair is always equals to the number of outer atom Two floating atoms two bond pair. We must have more than two. It's not possible. Okay, three chlorine atoms You'll see here three bond pair must be there Right, so it is geometries. What? Geometry is TBP diagonal bipyramid. What is the shape? Shape is linear All three lone pair presence in the corner of the triangle ICL 3 valence electron 7 into 4 28 So we have three bond pair see three outer atom three bond pair and two lone pair So it is T-shape geometry is again TBP and it is T-shape NO2 Nitrogen is 5 so the bond pair can never be more than the like More than yeah, yeah, it's not possible Valence electron NO3 so we have five for this six for this so six into three 18 18 plus one 19 plus 5 24 so we have three bond pair here and zero lone pair right, so it is a Trigonal planar Geometry and shape and O2 minus It is valence electron is 18 So it has two bond pair and one lone pair So it is also What is the geometry? Geometry is trigonal planar shape is V-shape 2 and 1 you see bent or V-shape understood Few more examples will do find out for CH4 NH3 H2 What is the number of valence electron you are getting here? Yes, here that thing does not apply since hydrogen form duplet. It does not form octet Okay, so what you need to do whenever I write down one note here if hydrogen is the outer atom if Hydrogen is the outer atom Then we divide it by two Then we divide it by two. Okay, so all the molecules you see the valence electron Is 8 So we divide it by two so number of you see this eight divided by two We are getting four here and no remainder So in this we have four outer atoms the number of bond pair four lone pair zero Here we have only three outer atoms out of four The number of bond pair is three and And lone pair is one three plus one four here outer atom is only two So number of bond pair is two and lone pair is two So all these are tetrahedral geometry. This one is pyramidal shape pyramidal And here the shape is V-shape V bent angle Understood all of you to find out the geometry and shape our next factors affecting the last you know thing for today Factors affecting bond angle the first one you write down effect of lone pair on central atom in that case we have to draw the structure Mother if you have different kind of atom then we have to draw the structure in that case Okay, we cannot do it by this method actual thing is that Louise Otter structure that you need to draw Okay, these are the trick so it may be it won't apply for all the molecules But with this particular thing you can do most of the question 99% of the question you can solve If there are different types of atoms hydrogen plus any other atoms present then actual thing is that only you find out the Well, it's electron draw Louise Otter structure, and then you find out the number of one You can find out from that right on as the number of electrons on lone pair on central atom increases bond angle decreases number of electrons on central atom increases best example we have theta one season theta three So theta one is maximum then theta two and then As the number of lone pairs on central atom increases bond angle decreases second one effect of multiple bond it on the multiple bond contains more charge And hence causes more repulsion more repulsion Which increases the bond angle which increases the bond angle if this is theta one This would be also theta one. This would be theta two So here because of the double bond theta one is greater than theta multiple bond causes more repulsion Multiple bond contains more charge causes more repulsion bond angle increases effect of electronegativity of central atom electronegativity of Central atom right on as the electronegativity of central atom increases Bond angle increases as the electronegativity of central atom increases bond angle increases NH3 and PS3 You see what happens here obviously theta one is the bond angle here Theta two is the bond angle here then the theta one the bond angle is greater than theta two Why it happens you see Since nitrogen is more electronegative it drags the bond pair of electron towards its side. So here the bond pair electrons are Towards the nitrogen atom hence they are coming closer and this tendency is more because the more electronegativity of nitrogen They are coming closer hence produces more repulsion and the bond angle expand here. It our one is more than fourth one effect of Electronegativity you want me to go back from okay. Just a second of outer atom. I'll share the notes anyways electronegativity of down as the electronegativity of outer atom increases Bond angle Decreases electronegativity of outer atom increases bond angle decreases just reverse of the previous one But in this you have some we have some exception that you must remember In case of H2O the bond angle is theta one In case of F2O the bond angle is theta two in case of Cl2O the bond angle is theta three Right, this is an exception here. Here the order is theta three is maximum then theta two and then theta one Right, this is an exception. You must remember one more exception. We have here in case of PF3 and ph3 The bond angle of pf3 is more than To that of ph3 and this is also an exception Understood. Yes, ideally it should be chlorine should be lesser least then chlorine and then edge But it is other way actually double bond will have the mole preference When you have a double bond present, so just simply consider one pair look one pair repulsion fine guys So we are done for this for the session today. Okay. Next class you remind me will start the new theory here Theory of bonding that is balance bond theory. Okay, so all of you write down the heading balance bond theory will start this Next class It's the Lewis start I'm sorry. This is See the valence electron you are getting is 32 the sulfur oxygen oxygen oxygen and oxygen one two three four five six seven eight and each of these oxygen atom has six lone pairs or three lone pairs electron There's no lone pair on the sulfur atom Now in this the negative charge the formal charges negative negative negative negative and plus two on the sulfur atom According to the rule when you have a hypervalent atom the charge on the central atom should be either the charge on the iron Which is minus two or zero Right in order to make it zero will shift one pair of electron from oxygen to Make a double bond over here. So one pair will shift here. Another pair will shift here The advantage of this is what both oxygen atom will have zero formal charge Subtle sulfur will also have zero and oxygen has two negative charge here This is the Lewis structure of SO4 to minus according to the Rules that we have Now, why can't we make any double bond here and make it to minus two because if you do this then sulfur will have Two negative charge oxygen will have zero charge here If any negative charge you have to place then we'll try to place the negative charge on more Electro negative atom, which is oxygen here not sulfur That's why this the structure is more stable than the other one. Hence the structure Fine. So heading all of you write down valence bond theory will start in the next class Let me know this valence bond theory We have to start in this only we'll see the bonding the hybrid action theory will discuss here only Okay, all for the modules questions related to VSE PR. I'll share one PDF also with you on this VSE PR Thank you guys. Take care. Bye. Bye