Question
Question: Ionisation enthalpy ![](https://cdn.pureessence.tech/canvas_127.png?top_left_x=0&top_left_y=1347&wid...
Ionisation enthalpy for the elements of group 13 follows the order.
A
B > Al > Ga > In > Tl
B
B< Al < Ga < In < Tl
C
B<Al> Ga < In >Tl
D
B > Al < Ga > In < Tl
Answer
B > Al < Ga > In < Tl
Explanation
Solution
: The decrease in ionisation enthalpy from B to Al is associated with increase in size. The observed discontinuity in the ionisation enthalpy values between Al and Ga, and between In and Tl are due to inability of d – and f – electrons, which have low screening effect, to compensate theincrease in nucler charge.