Bond Angles

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

Moderators: Chem_Mod, Chem_Admin

Bijan Mehdizadeh 1B
Posts: 73
Joined: Fri Sep 28, 2018 12:15 am

Bond Angles

Postby Bijan Mehdizadeh 1B » Tue Nov 13, 2018 6:18 pm

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

Postby Tuong Nguyen 2I » Tue Nov 13, 2018 6:29 pm

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

Postby Cole Elsner 2J » Tue Nov 13, 2018 6:36 pm

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

Postby Amy Dinh 1A » Wed Nov 14, 2018 7:29 pm

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

Postby Matthew Tran 1H » Wed Nov 14, 2018 7:36 pm

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.

Lia Inadomi 1I
Posts: 62
Joined: Fri Sep 28, 2018 12:15 am

Re: Bond Angles

Postby Lia Inadomi 1I » Wed Nov 14, 2018 7:38 pm

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

Postby Tatum Keichline 2B » Wed Nov 14, 2018 8:41 pm

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
Posts: 31
Joined: Fri Sep 28, 2018 12:18 am

Re: Bond Angles

Postby Kelly Zhang 1L » Wed Nov 14, 2018 9:11 pm

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

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

Re: Bond Angles

Postby anishathomas » Wed Nov 14, 2018 9:19 pm

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.

Return to “Determining Molecular Shape (VSEPR)”

Who is online

Users browsing this forum: No registered users and 1 guest