Common __ have 2,6, or 10 pi electrons, for N= 0, 1, or 2
__ might have 4, 8, or 12 pi electrons, for N=1,2,3.
Benzene is __, __, with a continuous ring of overlapping p orbitals. There are six pi electrons in benzene (three double bonds in the classical structure), so it is a (4N+2) system, with N=1. __ predicts benzene to be __.
- if the number of pi electrons in the cyclic system is (4N+2), the system is aromatic
- N is an integer, commonly 0, 1, 2, or 3
- Huckel's rule