WHY does calcium belong in group 2?

Answer 1

The Periodic Table is organized in order of increasing number of electrons. Column-wise, the elements are divided into groups. With the exception of the transition metals in the middle of the period table, all the other groups have the same number of valence electrons within each groups.

Calcium has 2 valence electrons, meaning that there are two electrons in its outermost shell of electrons. All group 2 elements have two valence electrons. So calcium belongs in group 2. It is also there because of how the table is arranged in the order of increasing atomic number

Answer 2

Calcium belongs in group 2 of the periodic table because it has two valence electrons in its outer shell, which it needs to lose in order to become stable. Elements in group 2 typically lose two electrons to achieve a stable electron configuration and form 2+ cations.