Bond Angles

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

Posts: 73
Joined: Fri Sep 28, 2018 12:15 am

Bond Angles

Is there a way to calculate bond angles, or do you just have to estimate them with a range? And if you can only estimate, how would you know that the bond angle for clo2+ in 7th edit 2E 5 is slightly less than 120 degrees?

Tuong Nguyen 2I
Posts: 71
Joined: Fri Sep 28, 2018 12:26 am
Been upvoted: 1 time

Re: Bond Angles

I believe that bond angles in VSEPR models are just something that you have to memorize with certain shapes. There's no way to calculate bond angles as of right now.

Cole Elsner 2J
Posts: 88
Joined: Fri Sep 28, 2018 12:25 am

Re: Bond Angles

We weren't taught any set formula to calculate any bond angles. I believe the only way for us to really have an idea of what the angle may be is to memorize the shape of a molecule and what bond angles it yields.

Amy Dinh 1A
Posts: 62
Joined: Fri Sep 28, 2018 12:23 am

Re: Bond Angles

I also agree that there's no calculations to determine bond angle; however, knowing how many lone pairs and bonded pair electrons may aid you in knowing the shape of the compound and then the assumed bond angle.

Matthew Tran 1H
Posts: 165
Joined: Fri Sep 28, 2018 12:16 am

Re: Bond Angles

I think you should be familiar with the generic bond angles for shapes, for example, 109.5 degrees for tetrahedral, 120 degrees for trigonal planar, etc. These angles hold true unless there are lone pairs, which would reduce the bond angles slightly. In these cases, you would just have to approximate the bond angles as there is no way to calculate the bond angles. For example, CH4 (methane) has bond angle of 109.5 since it is tetrahedral but NH3 (ammonia) has a bond angle slightly less than 109.5 degrees since it has a tetrahedral electronic structure (but trigonal pyramidal shape) with a lone pair.

Posts: 62
Joined: Fri Sep 28, 2018 12:15 am

Re: Bond Angles

I believe that for certain molecular shapes you will know the angles ie trigonal planar is 120 degree angles, but for the case of molecules with lone pair electrons those you will have to give a range because there is no way to calculate the actual bond angle just by looking at VSEPR. Hope that helps!

Tatum Keichline 2B
Posts: 64
Joined: Fri Sep 28, 2018 12:26 am

Re: Bond Angles

You just have to know the bond angles from VSEPR, and Dr. Lavelle was saying 360/# of bonds, but that doesn't always work.

Kelly Zhang 1L
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Joined: Fri Sep 28, 2018 12:18 am

Re: Bond Angles

What is the molecular geometry that gives bond angles of 106 degrees?

anishathomas
Posts: 35
Joined: Fri Sep 28, 2018 12:25 am

Re: Bond Angles

I think for most of them you just have to memorize it for the fastest way on an exam. However it will help to realize that when there are lone pairs, that will affect the bond angles. For exme, if there are four areas of electron densities, but one of them is occupied by lone pirs, and sy the shape is trigonal pyramidal instead of tetrahedral, we can estimate the bond angle to be less than 109.5.