Most of the Alkali Metal Salts Are Soluble in Water

Most of the alkali metal salts are soluble in water while many alkaline earth salts have very low solubilities. Why is this so?

A) The alkali metal cations are smaller than the alkaline earth cations and are more easily hydrated.
B) The alkali metals have lower ionization energies than alkaline earth elements.
C) The alkaline earth salts have much greater lattice energies than the alkali metal salts.
D) The alkaline earth metals have greater heats of atomization than the alkali metals.
E) Alkaline earth cations have very low heats of hydration.