Question

what are heteroatoms ?

Answer 1

Here is your answer.

Hydrocarbons which posses other elements than carbon and hydrogen in them are said to be hetero atoms.
Example:
Oxygen is hetero atom in ethanol ( C2H5-O-H)
Similarly Nitrogen is the hetero atom in Ethyl amine ( CH3-CH2- NH2)

Hope it helps you.

Answer 2

heteroatoms are those which is non carbon in nature i e. not a carbon or not a hydrogen