Aromatic compounds are those which resemble benzene in chemical behaviour.
They contain alternate single and double bonds in a cyclic structure.
They undergo substitution reactions rather than addition reactions
Criteria for Aromaticity- Contribution by Huckel
1. Delocalisation: The molecule should contain a cyclic cloud of delocalized Pi electrons above and below the plane of the molecule.
2. Planarity:For a molecule to be aromatic, the ring must be planar.
3. Huckel Rule: the pi electron cloud must contain a total of 4n+2 pi electrons whre n is an integer equal to 0,1,2,3.
Benzene has 6 pi electrons, napthalene has 10.