Lewis Structures- resonance  [ENDORSED]

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Irma Ramos 2I
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Joined: Fri Sep 29, 2017 7:07 am

Lewis Structures- resonance

Postby Irma Ramos 2I » Fri Oct 27, 2017 9:25 pm

Lewis structures with resonance, for example nitrate, when asked to draw the lewis structure would we be able to draw any of the three possible structures that we went over in class and still have the correct answer or is there one preferred over the others?

Hannah Guo 3D
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Joined: Fri Sep 29, 2017 7:06 am

Re: Lewis Structures- resonance

Postby Hannah Guo 3D » Fri Oct 27, 2017 9:56 pm

In the real world, nitrate ions are always changing between the three resonance structures because when electrons move to different locations, one structure can easily change to another one. I wouldn't say there is a preferred structure, but we should look at what the questions ask us to do.

Christy Lee 2H
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Re: Lewis Structures- resonance

Postby Christy Lee 2H » Fri Oct 27, 2017 10:21 pm

For the nitrate example, any of the three resonance structures are correct if the questions just asks for a lewis structure. However, we just have to understand that the real structure is a blend of the three. For other examples though, we would have to look at formal charges to determine which is the best lewis structure.

Zane Mills 1E
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Re: Lewis Structures- resonance

Postby Zane Mills 1E » Sat Oct 28, 2017 11:02 am

Adding to this, when drawing resonance structures if there are multiple structures with identical formal charges the more electro-negative elements should have the negative formal charge, while less EN elements could hold the positive charge (if necessary). In the above example, it would likely just be a good idea to draw each of the equal resonance structures with a <---> between them, indicating their ability to switch between resonance forms easily.

Shreya Ramineni 2L
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Re: Lewis Structures- resonance  [ENDORSED]

Postby Shreya Ramineni 2L » Sat Oct 28, 2017 4:30 pm

For resonance, you draw all of the possible structures and connect them by showing resonance through double sided arrows (<---->).

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