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.

Given below are two statements. One is labelled as assertion (A) and the other is labelled as reason (R).

Assertion (A): Size of BK⁺³ ion is less than NP⁺³ 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 the atomic number increases, ionic size decreases due to Lanthanoid/Actinide contraction.