Which is an example of a covalent bond? Chlorine accepts an electron from calcium to form a stable bond. Ions in a bar of pure iron are surrounded by a large number of valence electrons. There are less than 16 valence electrons in 2 chlorine atoms, but they form a stable bond.

A covalent bond occurs between nonmetal elements, or between a nonmetal and hydrogen or between hydrogen atoms. In this kind of bond, the atoms share electrons.

In the first case, chlorine is accepting electrons from calcium, which is donating. Chlorine is a nonmetal, but calcium is a metal. They form an ionic bond.

In a metal bar, like iron, there are metallic bonds: the metal loses electrons, and the cation (the metal ion) is surrounded by these electrons.

So, in a bond between two chlorine atoms, both nonmetal, there is a sharing of electrons. Both have 7 electrons in the valence shell, and each one shares one electron. They both will have 8 electrons, but the total will be 14 electrons, less than 16.