Yes, NH2 is a functional group. It is known as the amino group and is commonly found in organic compounds such as amino acids and amines. The amino group consists of a nitrogen atom bonded to two hydrogen atoms.
In organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. The NH2 group is highly reactive and can participate in various chemical reactions, making it an important functional group in biochemistry and organic synthesis.
For example, in amino acids, the NH2 group is one of the key functional groups that contribute to the formation of peptide bonds, which link amino acids together to form proteins.