PDA

View Full Version : Increasing Bond Angles


MysticDude
Oct24-10, 02:44 PM
1. The problem statement, all variables and given/known data
Another chemistry question :D
Arrange the following AFn species in order of increasing F-A-F bond angles: BeF3, BeF2, CF44, NF3, and OF2.


2. Relevant equations



3. The attempt at a solution
Ok so I'm thinking that it would be OF2 first because it's bent and both of the lone pairs decrease the bond angles by around 2° each, making them 105.5°.

Next should be NF3, the lone pair decreases the bond angle by 2° making it 107.5°.

Then I think that CF4 is next because it would angles around 109.5°.

Next one the list I chose BeF3 because the bond angles would be 120°.

Last I chose BeF2 because it is linear, making the bond angles 180°.

So in the end OF2 -> NF3 -> CF4 -> BeF3 -> BeF2

I hope that you can understand my logic and see if I'm right or wrong. Thanks for any help.

k-rod AP 2010
Nov2-10, 06:32 PM
As far as I can see your methodology is correct and you seem to have the right answer. Just be careful and make sure how much the lone pairs decrease the bond angles for each distinct molecule because it can vary, for example 2 degrees for molecule A and 4 degrees for molecule B

MysticDude
Nov2-10, 08:58 PM
Okay thanks for the answer. This question is pretty old though and I'm already past the unit in the class.