Question

Which of the followings are consequences of poor shielding effect of d and f orbital?

• A. Atomic radius of Ga is smaller than Al
• B. Irregular trends in the I.E. values are observed between Al and Ga
• C. Ionisation energy of Tl is greater than In
• D. Ionisation energy of Al is lesser than B

Answer 1

Answer: (A), (B), (C)

Ionisation energy of Tl is greater than In

Going down the group after Al, the elements will have d and f orbitals in their electronic configuration. Due to the poor shielding effect of d and f orbitals, the nuclear charge below Al increases and this results in smaller size of Ga than Al.
Due to their smaller size Ionisation energy increases and shows irregular trend.
Due to higher nuclear charge of Tl, it has higher ionisation energy than In.
Since there are no presence of d orbital in B and Al it does not have any consequence over B and Al.
So, the correct statements are (a), (b) and (c).