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lone pairs

Posted: Sun Nov 18, 2018 1:31 pm
by Ruiting Jia 4D
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?

Re: lone pairs

Posted: Sun Nov 18, 2018 1:40 pm
by George Ghaly 2L
Yes, Dr. Lavelle goes into great detail about this phenomenon as lone electrons repel atoms away.

Re: lone pairs

Posted: Sun Nov 18, 2018 2:39 pm
by Lasya Gudipudi 1A
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.

Re: lone pairs

Posted: Sun Nov 18, 2018 2:42 pm
by Dayna Pham 1I
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.

Re: lone pairs

Posted: Sun Nov 18, 2018 3:40 pm
by shouse1f
how do lone pairs affect the shape and repulsion in a molecule

Re: lone pairs

Posted: Sun Nov 18, 2018 3:45 pm
by davidbakalov_lec2_2L
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.

Re: lone pairs

Posted: Sun Nov 18, 2018 9:57 pm
by Bruce Chen 2H
Lone pairs are able to change the bond angle and shape as they push the other bonds around.

Re: lone pairs

Posted: Sun Nov 18, 2018 10:28 pm
by Kristy 1F
The repulsion of the lone pairs will change the angle between atoms which means it will change the shape of molecules

Re: lone pairs

Posted: Sun Nov 18, 2018 10:39 pm
by 405021651
The lone pair will take up more space so I believe its angle will increase while the other angles decrease

Re: lone pairs

Posted: Sun Nov 18, 2018 10:46 pm
by duenezjuleny1D
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

Re: lone pairs

Posted: Sun Nov 18, 2018 10:48 pm
by Sheridan Slaterbeck 1J
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.

Re: lone pairs

Posted: Sun Nov 18, 2018 10:52 pm
by Rachel-Weisz3C
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.