JEE Main · 2026 · 02 Apr 2026 · Shift 2 · Classification of Elements and Periodicity

The second ionization enthalpy removes an electron from the singly charged cation, and for the boron family these values run $\text{B}>\text{Ga}>\text{Al}$, since the poor shielding by the intervening $3d$ electrons makes the second electron of gallium harder to remove than that of aluminium. The order quoted in Statement-I, $\text{B}>\text{Al}>\text{Ga}$, is therefore wrong. For the carbon family the first ionization enthalpy decreases down the group with a terminal reversal, giving $\text{Si}>\text{Ge}>\text{Pb}>\text{Sn}$, the rise at lead arising from the poor shielding of its $4f$ and $5d$ electrons. Statement-II reverses this and is also wrong. Both statements are false.