There are two ways atoms join to make compounds: Metal atoms can give up electrons to non metals. This causes the metal atoms to become negative ions and the non metal atoms to become positive ions. Since opposite charges attract each other the ions stick together to form a new substance and the bond type is called ionic.
Atoms can also share one or more pairs of electrons to form single, double or triple bonds (each bond is a pair of electrons). This type of bond is called covalent.
Atoms can also share one or more pairs of electrons to form single, double or triple bonds (each bond is a pair of electrons). This type of bond is called covalent.