## Figuring Out Bond Angle

(Polar molecules, Non-polar molecules, etc.)

Ananta3G
Posts: 62
Joined: Wed Sep 18, 2019 12:19 am

### Figuring Out Bond Angle

Hello! How does one figure out the bond angle of a certain molecular geometrical shape? I know you can find it based on what kind of shape it is ie linear = 180 degrees, but how do you know when it is slightly more or less than the typical/definitional bond angle given by the general shape? ie sometimes the answer is "slightly less than 120 degrees" and not 120 degrees. Thanks!

Wendy 1E
Posts: 111
Joined: Sat Aug 17, 2019 12:17 am
Been upvoted: 2 times

### Re: Figuring Out Bond Angle

If the central atom has lone pairs, it will cause more electron-electron repulsion, which will result in a molecule having a bond angle that is smaller than usual (i.e. less than 120 degrees). You can think of this as if the electrons are "pushing away" the other bonds, which results in a smaller bond angle. For instance, the lone pair in a bent-shaped molecule, "pushes" away the other bonds, which results in a bond angle of fewer than 120 degrees between those bonds.

Sarah Nichols 4C
Posts: 52
Joined: Sat Aug 24, 2019 12:18 am

### Re: Figuring Out Bond Angle

When there is a lone pair, it has stronger repulsion than an atom, so it will force the atoms in the molecule closer together and slightly decrease the angle
This will also happen if one of the atoms is larger than the others

Montana James 4G
Posts: 46
Joined: Wed Sep 18, 2019 12:21 am

### Re: Figuring Out Bond Angle

Also you can't find out quantitatively how much smaller the distorted angle is, you can only determine that it is slightly smaller.