Assertion: On moving down the group, ionization enthalpy decreases.
Reason: With decrease in size of the atom, the force of attraction between the nucleus and valence electrons decreases.

Options

A. If both (A) and (R) are correct, but (R) is not the correct explanation of (A).
B. If both (A) and (R) are correct, but (R) is not the correct explanation of (A)
C. If (A) is correct, but (R) is incorrect.
D. If both (A) and (R) are incorrect.

Answer

C

Explanation

I.E. decreases down the group due to increase in atomic size and the outermost electron being increasingly farther from the nucleus, there is an increased shielding of the nuclear charge by the electrons in the inner levels.