a) Ionic bonds are the bonds between a metal and a nonmetal. Metals lost their electrons and nonmetals gain them. These bonds are the strongest so the melting and boiling points are the highest of all.
b) Covalent bonds are bonds between two nonmetals. The elements share electrons so these bonds are not as stronger as Ionic bonds, the melting and boiling points are high.
c) Metallic bonds are among metals and have high melting and boiling points.
