Question about Resonance Def

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Question about Resonance Def

Postby noelle_lipschutz_3F » Sun Nov 08, 2020 11:44 am

Can someone explain what resonance is?

Gwendolyn Hill 2F
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Re: Question about Resonance Def

Postby Gwendolyn Hill 2F » Sun Nov 08, 2020 11:46 am

Resonance is a blending of structures that have the same arrangement of atoms, but different arrangements of e-. The combination of all of the resonance structures is what results in the actual composition of the molecule. Dr. Lavelle talked about how for nitrate, each N-O bond has partial double bond character, which is a blend of the three different resonance structures we looked at in class. :)

Wil Chai 3D
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Re: Question about Resonance Def

Postby Wil Chai 3D » Sun Nov 08, 2020 11:56 am

The first definition Lavelle gave had to do with lewis structures: "some lewis structures have multiple bonds in different equivalent locations," and that resonance is needed "due to limitations in lewis Structures." Here I think he's basically saying that when you can draw a lewis structure multiple ways, like the NO3- ion where you can place a bond in multiple positions, you have resonance. So this is a good way to IDENTIFY resonance.

Later in the lecture, he gave a more specific def: "the blending of structures w/ the same arrangement of atoms but different arrangement of electrons." This means that the actual structure is a hybrid or average of each resonance structure, causing each bond to have what he called 'multiple bond character.'

Resonance also means that there are delocalized electrons, which don't 'belong' to a single atom or bond. Hope this helps!

Eliana Carney 3E
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Re: Question about Resonance Def

Postby Eliana Carney 3E » Sun Nov 08, 2020 1:09 pm

Hey Noelle!
Resonance is the idea that Lewis structures can have multiple bonds (ie not single bonds) in different locations. Basically, if you're looking at a Lewis structure and it has a multiple bond that can be placed somewhere else without creating a different molecule, there is resonance. This is how you might look a resonance when trying to identify it from a Lewis structure.
As for the actual definition of resonance, it "is a blending of structures with same arrangement of atoms but different arrangements of electrons". Essentially, resonance means that the real structures of these molecules don't usually have multiple or single bonds, but rather are composed of a sort of hybrid bond that spreads the bond lengths evenly around the molecule (ie each bond is the same length).
Hope this helps!

Madison Muggeo 3H
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Re: Question about Resonance Def

Postby Madison Muggeo 3H » Sun Nov 08, 2020 7:03 pm

Basically, if a structure can have a double or a triple bond in more than one position on the Lewis Structure, it means that there is resonance. In reality, the structure has a mixture of single or double/triple bond characteristics. This would lead to the bond length being shorter than a single bond but not as short as a double/triple bond.

Savannah Torella 1L
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Re: Question about Resonance Def

Postby Savannah Torella 1L » Sun Nov 08, 2020 7:23 pm

In simple terms, resonance is when a Lewis structure can show more than just simple bonds, ie double or triple bonds, and that these bonds can be placed anywhere on the structure and still make the structure true. For example, for NO3- a double bond can be placed between any N and O, as long as one double bond is placed.

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