above angle is the angle formed by two adjacent neighbouring atoms in a molecule. And we're gonna say when the central element has zero lone pairs, it possesses what we call an ideal bond angle. Now this ideal bond angle is the optimal angle elements take in order to minimize repulsion between one another. And we're gonna say when the central element has one or more lone pairs, it's ideal, bond angle will be decreased. So for example, a particular here we said that the bond angle is the angle by two adjacent neighbouring atoms in a molecule. So you'll have a central element, It will be connected to two surrounding elements. And you're gonna say that the angle bond angle is this portion here, if we have three surrounding elements, the bond angle would be here. It would also be here as well as here. And if we had a lone pair, the bond angle would be in here. Now again remember once we have a lone pair on our central element, the bond angles going to decrease. This decrease will be represented as a blue image for a smaller bond angle. All right, so now that we know what a bond angle is and how lone pairs helped to reduce our ideal bond angle values, Let's pick on the next video and take a deeper look in terms of the exact values with these bond angles.

here, we can say that bond angles can further differentiate molecules that possess the same number of electron groups. So when we have two electron groups, them is we have only one possibility are central element having to surrounding elements. In that case we have an ideal bond angle because our central element can't have a lone pair, So for electron group of to the ideal bond angle is 180°. When we have three electron groups around the central element, we have two possibilities. One were the central element just has three bonding groups And zero lone pairs. In this case because there are no lone pairs on the central element, we have an ideal bond angle of 120°. But remember, another possibility exists where we could have two bonding groups And one lone pair. The presence of the lone pair means that our bond angle will decrease from its ideal value. All you need to say at this point is if the ideal bond angle for three electron groups is 1 20 Then when it gets decreased it'll be less than 120. You don't have to give an exact number. You can just say less than 120. All right, So when we have four electron groups, we have three possibilities. We have four bonding groups, zero lone pairs, zero lone pairs means we have an ideal bond angle of 109. degrees, But we also have three bonding groups and one lone pair. So here we just say that our bond angle now is less than one of 9.5. And then we have our last possible option to bonding groups to lone pairs. Here We expect the bonding the bond angle to be again less than one of 9.5. And in fact, we'd say that it's even a little bit less than 195 than this one, because the presence of more lone pairs only helps to further reduce the bond angle. So just remember when we have no lone pairs on the central element, we have an ideal bond angle. The inclusion of any lone pairs after this means that our bond angle will be decreased from this ideal bond angle value.