Reason why lone pairs decrease bond angle

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Jeffrey Fenn 1G
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Joined: Wed Sep 30, 2020 10:08 pm

Reason why lone pairs decrease bond angle

Postby Jeffrey Fenn 1G » Wed Nov 25, 2020 12:54 am

Hi, so I understand that lone pairs decrease bond angles, for example NH3 goes from 109.5 to 107, but someone explain why this happens? Does it have to due with the energy of the lone pairs being higher?

Selena Quispe 2I
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Re: Reason why lone pairs decrease bond angle

Postby Selena Quispe 2I » Wed Nov 25, 2020 1:24 am

Hi! So lone pairs have the greatest repulsion and they occupy a larger volume so they will push the bonding pairs down and slightly distort the bond angles by forcing the bond pairs together slightly. I hope this helps!!

Jessica Manriquez 1H
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Joined: Wed Sep 30, 2020 9:47 pm

Re: Reason why lone pairs decrease bond angle

Postby Jessica Manriquez 1H » Wed Nov 25, 2020 1:37 am

Since lone pairs have very high repulsion, they push bonding pairs away from themselves and closer to other bonding pairs, therefore decreased bond angles between them. Hope this helped :)

Inderpal Singh 2L
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Re: Reason why lone pairs decrease bond angle

Postby Inderpal Singh 2L » Wed Nov 25, 2020 1:42 am

Lone pairs actually have the highest repulsion, meaning they push the bonds farther away compared to if they were not lone pairs. This causes the bond angles to decrease.

Sabrina Galvan 3J
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Re: Reason why lone pairs decrease bond angle

Postby Sabrina Galvan 3J » Wed Nov 25, 2020 2:14 am

Lone pairs have a greater repulsion in comparison to boned pairs. These lone pairs therefore force the bonded pairs close to one another, as the lone pairs take up a greater space due to the repulsion.

Kiyoka Kim 3C
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Re: Reason why lone pairs decrease bond angle

Postby Kiyoka Kim 3C » Wed Nov 25, 2020 6:45 am

I usually imagine it as the lone pairs being really repulsive that it pushes the atoms closer together causing the bond angles between them to decrease.

Kelly Tran 1J
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Re: Reason why lone pairs decrease bond angle

Postby Kelly Tran 1J » Wed Nov 25, 2020 9:40 am

Hi! Lone pairs occupy a larger volume, and the repulsion strength between a lone pair and a bonding pair is greater than that of a bonding pair and a bonding pair. Due to this, the lone pairs push down on the bonded pairs, distorting (decreasing) the bond angles. Hope this helps!

Pranav Daggubati 3C
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Joined: Wed Sep 30, 2020 9:35 pm

Re: Reason why lone pairs decrease bond angle

Postby Pranav Daggubati 3C » Wed Nov 25, 2020 10:16 am

Think of it like lone pairs being stubby areas of high density while bonds are more narrow and long. the stubby one will push the narrow ones together slightly to make room for itself, therefore making the bond angles smaller.


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