Answer;
Ionic compounds
Polyatomic ions bond with other ions to form ionic compounds.
Explanation;
-Polyatomic ions are ions which consist of more than one atom. For example, nitrate ion, NO3-, contains one nitrogen atom and three oxygen atoms.The atoms in a polyatomic ion are usually covalently bonded to one another, and therefore stay together as a single, charged unit.
-Ionic compounds are compounds made up of ions. These ions are atoms that gain or lose electrons, giving them a net positive or negative charge.Metals tend to lose electrons, so they become cations and have a net positive charge. Nonmetals tend to gain electrons, forming anions that have a net negative charge.