Calcium chloride is commonly used as a drying agent. Write the ionic formula for this compound.

The ionic formula for calcium chloride is CaCl2.

The octet rule in chemistry states that all atoms want eight valence electrons in their outermost orbital in order to be stable. The only exceptions are atoms that have only one orbital, such as hydrogen and helium. These atoms only need two electrons in order to be stable.

When a metal reacts with a nonmetal, such calcium and chlorine, an ionic bond is formed. Metals lose electrons to the nonmetals and become positively charged ions. The nonmetals gain electrons from the metals and become negatively charged ions.

Calcium is an alkaline earth metal with two valance electrons. Thus, calcium gives one of its two valence electrons to each of the chloride ions within calcium chloride. In this way, calcium drops to a lower and full electron orbital in order to fulfill the octet rule. Chlorine is a halogen with seven valence electrons. Therefore, each chlorine atom needs only one more electron in order to fulfill the octet rule. Thus, each chlorine atom receives one of calcium’s two electrons in order to fulfill the octet rule.