Question

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

Assertion A : The size of the ${\mathrm{BK}}^{3+}$ ion is less than the ${\mathrm{Np}}^{3+}$ion.

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

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

• A. A is false but R is true
• B. Both A and R are true but R is not the correct explanation of A
• C. A is true but R is false
• D. Both A and R are true and R is the correct explanation of A

Answer 1

The correct option is C

A is true but R is false

Answer (C)

Explanation for correct option:

Size of ${}_{97}\mathrm{BK}^{3+}$ion is less than that of ${}_{93}\mathrm{Np}^{3+}$ . As atomic number increase ionic size decreases. It is due to actinoid contraction.

Hence option (C) is correct option.