The amine functional group is a chemical group consisting of a nitrogen atom bonded to hydrogen atoms or organic groups. It is characterized by the NH2 functional group. Unlike the tetrahedral shape common in most sp3 hybridized molecules, the nitrogen atom in an amine is sp3 hybridized but exhibits a pyramidal shape due to the presence of a lone pair on nitrogen. This lone pair repels the bonding pairs, resulting in the pyramidal arrangement.