lone pairs

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

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Jennifer Lathrop 1F
Posts: 71
Joined: Sat Dec 02, 2017 3:00 am

lone pairs

Postby Jennifer Lathrop 1F » Tue Nov 20, 2018 1:35 pm

Do lone pairs on non central atoms affect the shape of the molecule?

Tam To 1B
Posts: 72
Joined: Fri Sep 28, 2018 12:25 am

Re: lone pairs

Postby Tam To 1B » Tue Nov 20, 2018 1:48 pm

I believe lone pairs on non central atoms would affect the polarity of the molecule and create a dipole, but it shouldn't affect the overall shape of the molecule.
For example, with CH2F2 has a tetrahedral shape. However, F has lone pairs. This would just mean that the molecule is polar, but the shape remains the same.

Jamie Hsu
Posts: 31
Joined: Fri Sep 28, 2018 12:19 am

Re: lone pairs

Postby Jamie Hsu » Tue Nov 20, 2018 2:20 pm

Lone pairs on non central atoms should not affect the shape of the molecule

Meachelle_Lum_1I
Posts: 92
Joined: Fri Sep 28, 2018 12:24 am

Re: lone pairs

Postby Meachelle_Lum_1I » Tue Nov 20, 2018 3:06 pm

No, I believe only lone pairs on central atoms would affect the shape. This is why the trigonal pyramidal shape (3 bonded and 1 lone pair) has a bond angle that’s slightly less than a tetrahedral (4 bonded and 0 lone pair) bond angle of 109.5 degrees.
Lone pairs on non central atoms do affect the repulsion strength however. Lone-lone>lone-bond>bond-bond.

Sameen Mahmood 3D
Posts: 37
Joined: Wed Jun 13, 2018 3:00 am

Re: lone pairs

Postby Sameen Mahmood 3D » Tue Nov 20, 2018 3:08 pm

They affect neighboring atoms slightly by pushing on them but they don't create significant changes in bond angle (think CH4 vs. CH3Cl).


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