Question:
Ionisation enthalpy (∆i H1 kJ mol–1) for the elements of Group 13 follows the order.
(i) B > Al > Ga > In > Tl
(ii) B < Al < Ga < In < Tl
(iii) B < Al > Ga < In > Tl
(iv) B > Al < Ga > In < Tl
Solution:
Option (iv) B > Al < Ga > In < Tl is the answer.