Answer is Nitrogen atom.
Explanation: Amino groups are the functional groups in which Nitrogen atom is attached to hydrogen atoms, alkyl groups, aryl groups or the combination of these three. The Compounds that contain Amino group as a functional group is known as Amine.
Amines are classified as : Primary (1°), Secondary (2°), Tertiary(3°) and Quaternary (4°)
Primary amino groups are the ones in which Nitrogen atoms is covalently attached to 2 H-atoms and 1 alkyl or aryl group.
Secondary amino groups are the ones in which Nitrogen atom is covalently bonded to 1 H-atom and two alkyl or aryl groups.
Tertiary amino groups are the ones in which Nitrogen atom is covalently attached to only 3 alkyl or aryl groups.
Quaternary amino groups are the ones in which Nitrogen atom is covalently attached to 4 alkyl or aryl groups forming an ammonium salt.
The Atom which is covalently bonded to 2 H-atoms is Nitrogen atom.
