The correct explanation for why calcium typically forms a 2+ ion but not a 3+ ion is:
b) Calcium will lose two valence electrons to achieve the stable configuration of argon.
Calcium, which is located in group 2 of the periodic table, has two electrons in its outermost shell (valence shell). By losing these two valence electrons, calcium achieves a stable electron configuration that resembles that of argon, a noble gas. This configuration is much more energetically favorable for calcium compared to losing an additional electron to form a 3+ ion. Losing a third electron would require significantly more energy and would destabilize the atom, as it would then have an incomplete outer shell while trying to achieve a stable state. Therefore, forming a 2+ ion is the most logical and energetically favorable process for calcium.