AX2E2

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

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Jade Fosburgh Discussion 2C
Posts: 59
Joined: Fri Sep 29, 2017 7:07 am

AX2E2

Postby Jade Fosburgh Discussion 2C » Sun Nov 19, 2017 5:56 pm

Why is a molecule such as H2S not linear? Since there are two pairs of lone electron pairs, wouldnt it make sense that they arrange themselves to give the molecule a linear shape because the angle would then be 180 degrees, which is farther away then a bent shape. Isn't the whole point of the VSEPR theory to make models for atoms where they are farthest away from eachother as possible?

Nora Sharp 1C
Posts: 53
Joined: Sat Jul 22, 2017 3:00 am

Re: AX2E2

Postby Nora Sharp 1C » Sun Nov 19, 2017 6:15 pm

The molecule is not linear because both lone electron pairs have more repulsion than electrons from atoms bonded to the central atom, and there are four regions of electron density around the atom. Keep in mind that the "bent" shape is not entirely flat; the regions of electron density are spaced out similarly to a tetrahedral formation:
https://qph.ec.quoracdn.net/main-qimg-5 ... 16c12.webp

So in a case with four regions of electron density, it would be harder to achieve that "linear" shape because the optimal formation would not be linear even if the lone pairs were bonded atoms.

Also, because the repulsion of the lone pairs are stronger, it is more favorable for the bonded atoms to be pushed together than for them to form a linear shape.

Elika Asis 3C
Posts: 19
Joined: Fri Sep 29, 2017 7:07 am

Re: AX2E2

Postby Elika Asis 3C » Sun Nov 19, 2017 11:40 pm

When there is a lone pair, it tends to repel the other bonds more, therefore making the angles of the bonds less, because the lone pair naturally just pushes the rest away further, but it all nears the same degrees of angle, so they'll usually just express the angle as <90 or <120.


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