Question

Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R:

Assertion A: Size of Bk³⁺ ion is less than Np³⁺ ion.

Reason R: The above is a consequence of the lanthanoid contraction.

In the light of the above statements, choose the correct answer from the options given below:

Options

• A is false but R is true.

• Both A and R are true but R is not the correct explanation of A.

• A is true but R is false.

• Both A and R are true and R is the correct explanation of A.

Answer 1

Both A and R are true and R is the correct explanation of A.

Explanation:

₉₃Np³⁺, ₉₇Bk³⁺ as atomic number increases, ionic size decreases due to Lanthanoid/Actinide contraction.