resonance

[inaccensa]

This seems like a stupid q, but When I question about pyrrole, I chose C, I am thinking that since it has more electrons, it will carry a positive charge. But the correct answer is A, since additional bonds to Nitrogen gives you a positive charge. I'm confused since, in the first example, electron deficient carbon carries a positive charge.

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[VooDooo327]

Nitrogen has one lone pair. If it were to make a bond it would be positive (ie. NH4+). The only way it is negative is if it has 4 bonds plus a lone pair. But, the lone pair is used to make the double bond to carbon. The lone electrons on nirtogen are BOTH pi electrons normally in pyrrole.

If you can follow this, 1) the lone pair on nitrogen makes a double bond to the carbon to the left of it. 2) The electron in that original C=C bond is pushed up to the other carbon giving it a - charge.

Hope it helps.

 

[inaccensa]

Nitrogen has one lone pair. If it were to make a bond it would be positive (ie. NH4+). The only way it is negative is if it has 4 bonds plus a lone pair. But, the lone pair is used to make the double bond to carbon. The lone electrons on nirtogen are BOTH pi electrons normally in pyrrole.

If you can follow this, 1) the lone pair on nitrogen makes a double bond to the carbon to the left of it. 2) The electron in that original C=C bond is pushed up to the other carbon giving it a - charge.

Hope it helps.

Omg that was so simple. When i was typing the q, I knew this will be a dumb q. Nevertheless, it cleared my concepts. Thanks. It is the lone pair in the nitrogen that are used, not the electrons from the double bond. If there were a carbon instead of nitrogen then A would be the correct ans?