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VSEPR shape and bond angles

Posted: Thu May 31, 2018 1:46 pm
by Taizha 1C
Hi, I read that molecules with the same VSEPR formula have the same shape, but differ in bond angle. How would I determine the difference between the bond angles in different molecules with the same shape and VSEPR formula? Also how would I be able to recognize the exceptions to this? In the book it gave the example SeCl6^2-.

Re: VSEPR shape and bond angles

Posted: Thu May 31, 2018 1:52 pm
by Bijal Luhar
I believe here you would be looking at the strengths of the bonds as a stronger bond would pull closer in one direction and therefore create a smaller angle.

Re: VSEPR shape and bond angles

Posted: Thu May 31, 2018 2:52 pm
by Hussein Saleh 1L
Taizha 1C wrote:Hi, I read that molecules with the same VSEPR formula have the same shape, but differ in bond angle. How would I determine the difference between the bond angles in different molecules with the same shape and VSEPR formula? Also how would I be able to recognize the exceptions to this? In the book it gave the example SeCl6^2-.


I recommend always to draw out the structures first when looking at such a question. Also remember that single bonds are long, double bonds are shorter, and triple bonds are shortest. That may contribute to the answer.

Oh dont forget to determine the shape that helps too!

Re: VSEPR shape and bond angles

Posted: Sun Jun 03, 2018 11:48 pm
by Taizha 1C
Okay, thank you! I believe I understand how to determine the difference now.

Re: VSEPR shape and bond angles

Posted: Sun Jun 03, 2018 11:55 pm
by Mariah Guerrero 1J
Do we have to know the specific bond angles for certain molecular shapes. For example, would it be acceptable to say (on a test) that sulfite ion, SO3 2-, have bond angles less than 109.5? Are approximations ok to state?

Re: VSEPR shape and bond angles

Posted: Mon Jun 04, 2018 4:46 pm
by Hussein Saleh 1L
Mariah Guerrero 1J wrote:Do we have to know the specific bond angles for certain molecular shapes. For example, would it be acceptable to say (on a test) that sulfite ion, SO3 2-, have bond angles less than 109.5? Are approximations ok to state?

Yes according to my PLF that is fine.