Final answer:
Calcium is a member of the alkaline earth metals and is located in Group 2. It has an electron configuration of [Ar]4s² and tends to lose both of its valence electrons to become a Ca²+ ion.
Step-by-step explanation:
Calcium is a member of the alkaline earth metals and is located in Group 2 of the periodic table. Its electron configuration is [Ar]4s², indicating that it has 2 valence electrons in its outermost electron shell. When forming a cation, calcium tends to lose both of its valence electrons and become a Ca²+ ion, which has an electron configuration of [Ar].