Answer: A molecule or compound is made when two or more atoms form a chemical bond, linking them together. The two types of bonds are ionic bonds and covalent bonds. In an ionic bond, the atoms are bound together by the attraction between oppositely-charged ions. For example, sodium and chloride form an ionic bond, to make NaCl, or table salt. In a covalent bond, the atoms are bound by shared electrons. If the electron is shared equally between the atoms forming a covalent bond, then the bond is said to be nonpolar. Usually, an electron is more attracted to one atom than to another, forming a polar covalent bond. For example, the atoms in water, H 2 O, are held together by polar covalent bonds.