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Bond Angles

Posted: Tue Nov 13, 2018 4:21 pm
by Clarissa Cabil 1I
When doing the homework, the solutions manual sometimes mentions how certain bond angles are "slight less than" 109.5º or 120º etc., but how can you tell if a certain shape is exactly, approximately, or slightly less than a certain degree?

Re: Bond Angles

Posted: Tue Nov 13, 2018 4:32 pm
by Rachel Yoo 1F
I think bond angles is something you just need to memorize by VSEPR

Re: Bond Angles

Posted: Tue Nov 13, 2018 4:46 pm
by Becky Belisle 1A
I think slightly less than has to do with lone pairs affecting what the angle normally is for a certain structure.

Re: Bond Angles

Posted: Tue Nov 13, 2018 5:36 pm
by Shibhon_Shepard
If you do draw them out, I would recommend explicitly writing the degrees somewhere just to be safe. This will also show your TA that you know what bond angle is actually there without having to actually draw out a 109.5 degrees vs a 120 degree angle.

Re: Bond Angles

Posted: Wed Nov 14, 2018 12:12 am
by Grace Kim 1J
https://www.angelo.edu/faculty/kboudrea/index/Handout_Lewis_VSEPR.pdf

I had the same question at first, but I used resources online (like the link above) to help me know the bond angles. I think as you do more problems, you start to familiarize yourself with the different angles according to their molecular shape and eventually memorize them!

Re: Bond Angles

Posted: Wed Nov 14, 2018 12:51 am
by Veronica Soliman 4H
We did a demo in class where if it’s 4 bonds, you just recall it’s a 3d shape so while you would think it is 90 degrees, it’s actually 109 because it’s 3dinensional. The first 3 are pretty self explanatory so 2 bonds would likely be farther apart and are at 180 degrees.