lone pairs

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

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Ruiting Jia 4D
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Joined: Fri Sep 28, 2018 12:27 am

lone pairs

Postby Ruiting Jia 4D » Sun Nov 18, 2018 1:31 pm

When there is a lone pair in a molecular shape, is it safe to say a general statement for how the other angles are affected? For example, saying that the angles of 90 and 180 degrees are slightly decreased due to the lone pair or to state a specific angle?

George Ghaly 2L
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Re: lone pairs

Postby George Ghaly 2L » Sun Nov 18, 2018 1:40 pm

Yes, Dr. Lavelle goes into great detail about this phenomenon as lone electrons repel atoms away.

Lasya Gudipudi 1A
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Re: lone pairs

Postby Lasya Gudipudi 1A » Sun Nov 18, 2018 2:39 pm

Yes. In the example we did in class with the sulfite ion, the bond angles are expected to be 109.5 degrees because they are arranged tetrahedrally, but the bond angles are actually 106 degrees due to the extra lone pair on the sulfur atom.

Dayna Pham 1I
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Re: lone pairs

Postby Dayna Pham 1I » Sun Nov 18, 2018 2:42 pm

I also agree that the lone pairs affect the angular geometry of the molecule. This is because of electron repulsion. However, lone pairs only are accounted for in the geometry of the molecule. The atoms in the molecule are what determines its shape.

shouse1f
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Joined: Fri Sep 28, 2018 12:18 am

Re: lone pairs

Postby shouse1f » Sun Nov 18, 2018 3:40 pm

how do lone pairs affect the shape and repulsion in a molecule

davidbakalov_lec2_2L
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Joined: Fri Sep 28, 2018 12:23 am

Re: lone pairs

Postby davidbakalov_lec2_2L » Sun Nov 18, 2018 3:45 pm

The specific decreases in angles caused by the presence of lone pairs can only be determined through experimentation, so you won't be expected to know the exact angle values.

Bruce Chen 2H
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Re: lone pairs

Postby Bruce Chen 2H » Sun Nov 18, 2018 9:57 pm

Lone pairs are able to change the bond angle and shape as they push the other bonds around.

Kristy 1F
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Joined: Fri Sep 28, 2018 12:19 am

Re: lone pairs

Postby Kristy 1F » Sun Nov 18, 2018 10:28 pm

The repulsion of the lone pairs will change the angle between atoms which means it will change the shape of molecules

405021651
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Joined: Tue Nov 14, 2017 3:03 am

Re: lone pairs

Postby 405021651 » Sun Nov 18, 2018 10:39 pm

The lone pair will take up more space so I believe its angle will increase while the other angles decrease

duenezjuleny1D
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Joined: Fri Sep 28, 2018 12:24 am

Re: lone pairs

Postby duenezjuleny1D » Sun Nov 18, 2018 10:46 pm

yes, you will not be expected to know the exact values as lone pairs do change the angle value but it is sufficient to say so or just state if it would for example be less than 180 or less than 109.5

Sheridan Slaterbeck 1J
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Re: lone pairs

Postby Sheridan Slaterbeck 1J » Sun Nov 18, 2018 10:48 pm

Lone pairs have a large affect on the shape of the molecule, lone pairs push nearby bonding pairs away creating a greater angle than if it were a bonding pair to bonding pair. Making the other angles decrease.

Rachel-Weisz3C
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Joined: Fri Sep 28, 2018 12:23 am

Re: lone pairs

Postby Rachel-Weisz3C » Sun Nov 18, 2018 10:52 pm

One example that Dr. Lavelle gave in class was that H2O has a lower bond angle than methane (CH4) because we know that methane has a bond angle of 109.5 degrees, and H20 is smaller than that, but we do not need to know that it is exactly 104.5 degrees.


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