The correct reason for smaller size of alkaline earth metal than that of alkali metal is that
A.Alkali metals have high value of nuclear charge
B.Alkali metal have low value of nuclear charge than✓ Correct
C.Alkali metal has high value of screening constant
D.Both (a) and (c)
Explanation
Alkali metals have low value of increased nuclear charge than alkaline earth metals. Hence, alkaline earth metals have smaller size than that of alkali metal.