No central atom

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

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No central atom

Postby JulieAljamal1E » Sat Nov 17, 2018 9:02 pm

When you have a molecule that doesn't really have a central atom i.e. N2H4, how do you determine the shape?

Lily Benitez 2G
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Re: No central atom

Postby Lily Benitez 2G » Sat Nov 17, 2018 9:10 pm

Each N will have one lone pair and 2 bond pairs and this will result in a "bent" shape.

Andie Jian 1D
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Re: No central atom

Postby Andie Jian 1D » Sat Nov 17, 2018 9:14 pm

I think you would treat it like each central atom is the center of its own shape. So since each nitrogen has 3 bonding pairs and 1 lone pair, the molecule would look like 2 trigonal pyramidal shapes put together. I'm not totally sure about this though, sorry!

Keshav Bhatnagar 1H
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Re: No central atom

Postby Keshav Bhatnagar 1H » Sun Nov 18, 2018 11:38 am

I believe the shape would be square planar. The two N atoms would be in the center with a bond between them and the H would surround them. This would result in 6 electron densities with two being lone pairs thus a square planar arrangement.

Hanlin Zhu 4G
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Re: No central atom

Postby Hanlin Zhu 4G » Sun Nov 18, 2018 11:57 am

I think we can think of the two nitrogen atom separately. Each of the nitrogen atom has a formula AX3N1 and a trigonal pyramidal shape.

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Re: No central atom

Postby Chem_Mod » Sun Nov 18, 2018 6:06 pm

Treat each N as a central atom and determine the shape relative to that atom. VSEPR works for a central atom and how things are located around it, not for big complex molecules. It does work for complex molecules, but you can only use it for describing for local environments.

Daniel Chang 3I
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Re: No central atom

Postby Daniel Chang 3I » Sun Nov 18, 2018 6:52 pm

Since there are only two N atoms, we would use each of those as the central atoms. It would result in a trigonal pyramidal shape with a 109.5 bond angle

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Re: No central atom

Postby katie_sutton1B » Sun Nov 18, 2018 6:54 pm

I think you have to look at N as the central atom. So you would draw the Lewis Structure relative to each nitrogen, and bond them together. This would make it trigonal pyramidal

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