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Can someone please explain what the "n" in 4n + 2 signifies? Does it mean # of pi electrons? # of pi bonds? # of sp2 hybridized atoms?
Hckel
- Thread starter NonTraditional3
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this is one of the conditions a molecule must satisfy to be considered aromatic. there is a specific number of electrons that the molecule must have to satisfy this equation where n can be 0,1,2,3,4....etc. it can only be a whole number. if it is not a whole number and the molecule satisfies all other conditions, then it is considered to be antiaromatic.
for example, you count the pi electrons in a molecule to be 12. it satisfies all other conditions (cyclic, conjugated etc).
4n+2=12
n=5/2; not a whole number, so the theoretical molecule would be antiaromatic.
however, if the pi electrons are 10 then
4n+2=10
n=2; the theoretical molecule is aromatic.
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So for benzene:
3 Pi Bonds = 6 pi e-
4n + 2 = 6
6 - 2 = 4
4/4 = n = 1
Whole number result for n, so benzene is aromatic....
3 Pi Bonds = 6 pi e-
4n + 2 = 6
6 - 2 = 4
4/4 = n = 1
Whole number result for n, so benzene is aromatic....
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Technically, it would just be NON aromatic since antiaromatic = 4n, but I don't think the MCAT is that nitpicky.
yes, just make sure it meets all other conditions and this. n needs to be whole and is just some arbitrary number used in the equation and doesnt represent anything significant, that i know of.