Bond Angles Concept 2

Jules Bruno
Was this helpful?
Bond angles can further differentiate molecules that possess the same number of electron groups. So if we take a look here, we have electron groups going from 2-6. In the first column we have our ideal bond angles because those central elements have zero long pairs. And then we start looking at what happens when we have 12 or three lone pairs involved. Now here, if we take a look to electron groups, there's only one possible shape that exists which is linear, it's bonding, go would be 180°. There's no possibilities of 12 or three lone pairs. So we take those out. When you have three electron groups, you could have possibly zero lone pairs which gives you an ideal bond angles of 120°. Or you can have one lone pair Here. All you need to remember is that we have three electron groups for this second structure and one of them is a lone pair. That just means our bond angle would be expected to be less than 120°. You're not expected to memorize an exact number. That's because there's a ton of different molecules that fit this description where we have a central element connected to two surrounding elements and one lone pair and be impossible to memorize every single one of those bond angles. Now, if you have four electron groups, you can have ideal Bonnie go if there are no lone pairs. So that would be one of 9.5. Once you start adding loan pairs or substituting in lone pairs, your bond angle decreases. So this will be less than 1 9.5. And this one has two lone pairs. So this one is even more less than one of 9.5. Now it's not gonna be a huge difference. Uh less than 19.5 here could be like 107 degrees. And here this might be one oh five or 106 degrees. So it's not a huge difference in bond angles. Next, if you have five electron groups, you have four different shapes. This one's a little bit different because here we have two different types of bond angles involved. Now remember if we have a five elektron system and imagine it being a sphere. Remember we have surrounding elements that exist along the equator and then we have ones that exist in the axial positions. And because of this, that's why we have two different types of bond angles involved. Now here for looking along the equator. So this and this, the bond angle would be 120°. And then if we're looking at the difference between the equatorial position in an actual bond, then that's what, that's 90°. Once we start adding loan pairs, these are just gonna decrease. So this will be less than 120 and this will be less than For the next one. This one here would be exactly 90°. And then here this would be linear in shape. So this would be 180°. So when it comes to five electron systems, it's pretty complex compared to the other. So this one you do have to remember a little bit in terms of certain bond angles. And then finally here, if we have six electrons groups were going to have three possible shapes here. Each one of these Gaps would be 90°. But once we have one loan period becomes less than 90° for each one. And then if you have too long pairs, it goes back to being 90° again. Okay, so those are the different types of bond angles we can discuss when it comes to these different shapes.