Question

How to determine if a compound is aromatic antiaromatic or nonaromatic?

Answer 1

for aromatic -- In organic chemistry, the term aromaticity is used to describe a cyclic, planar molecule with a ring of resonance bonds that exhibits more stability than other geometric or connective arrangements with the same set of atoms. 

for antiaromatic-- Antiaromaticity is a characteristic of a cyclic molecule with a π electron system that has higher energy due to the presence of 4n electrons in it.