What is the oxidation number of calcium (Ca) in CaF2?

The oxidation number of calcium (Ca) in CaF2 is +2. This is because fluorine (F) typically has an oxidation number of -1, and the overall charge of CaF2 is neutral. Since there are two fluorine atoms each with a -1 charge, the calcium atom must have a +2 oxidation number to balance the charges.