In which of the following options order of arrangement does not agree with
the variation of property indicated against it?
(i) Al3+ < Mg2+ < Na+ < F– (increasing ionic size)
(ii) B < C < N < O (increasing first ionisation enthalpy)
(iii) I < Br < Cl < F (increasing electron gain enthalpy)
(iv) Li < Na < K < Rb (increasing metallic radius)
In which of the following options order of arrangement does not agree with
the variation of property indicated against it?
(i) Al3+ < Mg2+ < Na+ < F– (increasing ionic size)
(ii) B < C < N < O (increasing first ionisation enthalpy)
(iii) I < Br < Cl < F (increasing electron gain enthalpy)
(iv) Li < Na < K < Rb (increasing metallic radius)

Option (ii) and (iiii) are the answers.

For increasing first ionization enthalpy, the order should be:
B < C < O < N
For increasing electron gain enthalpy, the order should be:
I < Br < F < Cl