Calcium is a metal, while sulfur is a nonmetal. Metals and nonmetals typically form ionic bonds, where the metal atom loses electrons to the nonmetal atom, resulting in the formation of positively charged metal ions and negatively charged nonmetal ions.
In the case of calcium and sulfur, calcium loses two electrons to sulfur, resulting in the formation of Ca2+ and S2- ions. These ions then attract each other electrostatically to form an ionic bond.
