What is aromaticity?

it is unexpected stability of compound or Aromaticity is the property associated with the extra stability of certain types of p systems. Fundamentally it arises from having the maximum number of electrons in the pi bondin...g molecular orbitals. As we will see, it is not restricted to benzene, substituted benzenes, 6-membered rings or just even hydrocarbons. The property of aromaticity is generally about a significant extra stability associated with a resonance delocalised structure. This extra stability moderates the reactivity of these systems compared to alkenes and means aromatics can be considered as their own functional group. The presence of aromatic systems can also influence the reactivity of functional groups directly attached to the aromatic system particularly in the benzylic position. Therefore it is important that you are able to recognise the aromatic systems aromaticity gives justifications for the high/low acidic or alkaline property of some compounds and why the biosystem select a certain double bond to be broken or oxidized.

a planar cyclic compound having complete resonance and 4n+2 pi electrons is aromatic. this phenomenon is aromaticity

Aromaticity is a chemical property describing the way in which a conjugated ring of unsaturated bonds, lone pairs or empty orbitals exhibits a stabilization stronger than would be expected by the stabilization of conjugate alone.