Repulsion Strength

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

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Reese - Dis 1G
Posts: 31
Joined: Fri Sep 28, 2018 12:15 am

Repulsion Strength

Postby Reese - Dis 1G » Thu Nov 15, 2018 10:27 pm

What does repulsion strength mean? I know the oder is lone-lone - lone-bonding - bonding-bonding, but what is that measuring?

Nicoline Breytenbach 3D
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Joined: Fri Sep 28, 2018 12:26 am
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Re: Repulsion Strength

Postby Nicoline Breytenbach 3D » Thu Nov 15, 2018 10:34 pm

Basically the degree to which electron lone pairs or bonding pairs repel other lone pairs or bonding pairs, contributing to the overall shape of the molecule. Higher repulsion means the electrons "want to be alone," and thus repel other electrons to a greater degree, sometimes even forcing them closer to each other if it means getting them away from itself. Think of magnets that repel, or push each other away without actually touching.

Gabriela Aguilar 4H
Posts: 30
Joined: Fri Sep 28, 2018 12:29 am

Re: Repulsion Strength

Postby Gabriela Aguilar 4H » Thu Nov 15, 2018 10:51 pm

It also helps in determining the shape of a molecule. Whether it is bent and therefore also the angles.

Kailey Nichols 4B
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Joined: Fri Sep 28, 2018 12:28 am

Re: Repulsion Strength

Postby Kailey Nichols 4B » Thu Nov 15, 2018 11:51 pm

yes, for example, if you look at SH2 compared to CH4, both molecules have the same number of "things" around the central atom, however, due to differences in lone pair-lone pair repulsion and bonding-bonding repulsion, the two molecules have very different shapes and bond angles.
Image-1.jpg

Esther Ahn 4I
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Joined: Fri Sep 28, 2018 12:29 am

Re: Repulsion Strength

Postby Esther Ahn 4I » Thu Nov 15, 2018 11:52 pm

The bonding electron is further from the central atom than a lone pair which is close to the nucleus (which is positively charged). Therefore, the VSEPR theory says that repulsion by the lone pair is greater than the repulsion by the bonding pair.

Yiwen Chen-3G
Posts: 30
Joined: Fri Sep 28, 2018 12:25 am

Re: Repulsion Strength

Postby Yiwen Chen-3G » Fri Nov 16, 2018 10:25 am

Because electrons are all negatively charged, they repel each other. Since the lone pairs are closer to the nucleus, their domain is smaller (more tightly bounded to the nucleus), which will result in a greater repulsion. For electrons in the bonds, there is a larger domain for them since they are further away from the nucleus. Therefore the repulsion would be smaller since it is negatively related to r^2(r is the distance between electrons.


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