Single/Double Bonds in Resonance

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

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Sean Sugai 4E
Posts: 56
Joined: Wed Sep 11, 2019 12:17 am

Single/Double Bonds in Resonance

Postby Sean Sugai 4E » Tue Nov 12, 2019 11:30 pm

Because single and double bonds are considered one unit in the VSEPR model, does it matter which of the Lewis structures contribute to the resonance structure? What's an example of this?

Michael Nguyen 1E
Posts: 120
Joined: Sat Aug 17, 2019 12:17 am

Re: Single/Double Bonds in Resonance

Postby Michael Nguyen 1E » Wed Nov 13, 2019 9:12 am

I don't believe resonance structures really impact the VSEPR model. The model only depends on the number of atoms bonded to the central atom and the number of lone pairs on the central atom. Whether or not there is resonance, single bonds, or double bonds, it does not affect a molecule's shape according to the VSEPR model.

Cynthia Gong 1L
Posts: 51
Joined: Fri Aug 09, 2019 12:15 am

Re: Single/Double Bonds in Resonance

Postby Cynthia Gong 1L » Wed Nov 13, 2019 11:28 am

Single, double ,and triple bonds are all considered one region of electron density in the VSEPR model. So regardless of resonance structures, the shape of the VSEPR model won't be affected.

Brian Tangsombatvisit 1C
Posts: 119
Joined: Sat Aug 17, 2019 12:15 am

Re: Single/Double Bonds in Resonance

Postby Brian Tangsombatvisit 1C » Wed Nov 13, 2019 11:30 am

All of the different Lewis structures contribute to the resonance model since it is a blend of these structures. Because of this, all of the bond lengths in this type of atom are the same, but are in between a single and double bond's length. However, resonance does not affect a molecule's bond angles or shape.

For example, the carbonate ion, CO3(2-) is trigonal planar with bond lengths of 120 degrees, even if one of its bonds is a double bond and it has resonance.

305421980
Posts: 101
Joined: Sat Sep 07, 2019 12:16 am

Re: Single/Double Bonds in Resonance

Postby 305421980 » Wed Nov 13, 2019 11:30 am

In lecture today he explained that resonance does not need to be explained by more that one VESPR model structure because each bond (single, double, triple) only counts as one. The example he used was carbonate and showed how you only need one VESPR structure.

Angela Patel 2J
Posts: 110
Joined: Sat Aug 24, 2019 12:17 am

Re: Single/Double Bonds in Resonance

Postby Angela Patel 2J » Wed Nov 13, 2019 12:17 pm

So all resonance structures for a molecule have the same shape? Is this always true?

Megan Vu 1J
Posts: 101
Joined: Thu Jul 25, 2019 12:15 am

Re: Single/Double Bonds in Resonance

Postby Megan Vu 1J » Wed Nov 13, 2019 12:32 pm

Each bond for the single, double, and triple are essentially the same as looking at all single bonds. Thus, the resonance structures do not change what type of structure it is because each bond acts as a single region of electron density, which remains true for these resonance structures.


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