Question

Why does carbon sp2 exist?

Answer 1

carbon atoms form sp^2 hybrid orbitals by the overlap of one s orbital and 2 p orbitals.

Explanation:

since carbon can form 3 sp^2 hybrid orbitals b the overlap of 1 s orbital and twp p orbitals there is an unhybridised orbital which can form a pi bond with another sp^2 hybridised carbon atom. Carbon itself has electronic confguration of 1s^2 2s^2 and 2p^2 which leaves the atom available for covalent bonding with other atoms in a way to have a bond angle of 120 degrees.