Is ammonium ion a nucleophile?
Ammonium ion is not a nucleophile. It has a nitrogen bonded to 4 hydrogen atoms.The valency of nitrogen is three so the fourth hydrogen atom is bonded by using nitrogen’s lone pair. Since the lone pair is used up by the hydrogen, nitrogen attains a positive charge, so it cannot be a nucleophile. For any atom or molecule to be a nucleophile it needs to have a lone pair of electrons or a negative charge.