Final answer:
Covalent bonds occur between two atoms of nonmetals, while ionic bonds occur between a metal and a nonmetal.
Step-by-step explanation:
Covalent bonds occur between two atoms of nonmetals. They form when electrons are shared between atoms and are attracted by the nuclei of both atoms. In covalent bonds, the electrons are shared equally or unequally depending on the electronegativity difference between the atoms. Ionic bonds, on the other hand, occur between a metal and a nonmetal. They result from the force of attraction that holds together oppositely charged ions.