Bond Angles

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

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Hannah_1G
Posts: 100
Joined: Wed Sep 18, 2019 12:22 am

Bond Angles

Postby Hannah_1G » Wed Nov 20, 2019 10:29 pm

Lone pairs on central atom cause the expected bond angles to be slightly less?

Marty Hockey
Posts: 47
Joined: Wed Sep 18, 2019 12:19 am

Re: Bond Angles

Postby Marty Hockey » Wed Nov 20, 2019 11:40 pm

Yes, for example, SO2 is angular with one lone pair so its angles are slightly less than 120 degrees.

Sanjana K - 2F
Posts: 102
Joined: Sat Sep 07, 2019 12:17 am
Been upvoted: 1 time

Re: Bond Angles

Postby Sanjana K - 2F » Thu Nov 21, 2019 12:03 am

The presence of lone pairs causes a higher repulsion since in terms of repulsion, lone pair---lone pair > lone pair---bonded atom > bonded atom---bonded atom, so the lone pair will take the place of a bonded atom and essentially exert greater repelling force against the other atoms, pushing them closer together (so the bonded angles will decrease).

Jialun Chen 4F
Posts: 108
Joined: Sat Sep 07, 2019 12:16 am

Re: Bond Angles

Postby Jialun Chen 4F » Thu Nov 21, 2019 12:27 am

That is correct. For instance, compounds with AX4 (tetrahedral) formula would have bond angles of 120 degrees, while AX3E (trigonal pyramidal) would have bond angles of slightly less than 120 degrees due to the lone pair.

Jainam Shah 4I
Posts: 130
Joined: Fri Aug 30, 2019 12:16 am

Re: Bond Angles

Postby Jainam Shah 4I » Thu Nov 21, 2019 12:41 am

You are correct. Lone pairs on the central atom repel against the electrons in the bonding pair. This causes the atoms attached via the bonding pair to come closer together due to the repulsion which is why the expected angle is less than normal

Joelle 3L
Posts: 50
Joined: Sat Jul 20, 2019 12:16 am

Re: Bond Angles

Postby Joelle 3L » Thu Nov 21, 2019 4:33 pm

Yes, lone pairs on the central atom would cause bond angles to be slightly less since electrons repel each other and this repulsion must be minimized by arranging them in a particular manner in 3D space.

Anvi Brahmbhatt 4A
Posts: 51
Joined: Wed Sep 18, 2019 12:21 am

Re: Bond Angles

Postby Anvi Brahmbhatt 4A » Thu Nov 21, 2019 5:31 pm

The lone pairs on the central atom would cause the expected bond angles to be slightly less because they repel against electrons in the bonding pairs.


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