Question

What is the oxidation number of Ca in ${\mathrm{CaCl}}_2$?

Answer 1

• During the formation of ${\mathrm{CaCl}}_2$, calcium loses 2 electrons thereby getting a charge of +2 while each atom of chlorine gains 1 electron, thereby getting a charge of -1.
• The oxidation number of Ca is the charge attained by it during the formation of ${\mathrm{CaCl}}_2$.