The first ionization energies of alkaline earth metal are higher than those of the alkali metals. This is because:

Options

A. there is increase in the nuclear charge of the alkaline earth metals
B. there is decrease in the nuclear charge of the alkaline earth metals
C. there is no change in the nuclear charge
D. none of the above

Answer

A

Explanation

The first I.Es. Of alkaline earth metals are higher than corresponding alkali metals due to higher nuclear charge. Smaller size and fully filled `ns^2` configuration.