(i). Ionization enthalpy: Because of high nuclear charge the ionization enthalpy of alkaline earth metals are higher than those of the corresponding alkali metals.
(ii). Basicity of oxides: Basicity of oxides of alkali metals are higher than that of alkaline earth metals.
(iii). Solubility of hydroxides: Solubility of hydroxides of alkali metals are higher than that of alkaline earth metals. Alkali metals due to lower ionization enthalpy are more electropositive than the corresponding group 2 elements.