Given below are two statement : one is labelled as Assertion A and the other is labelled as Reason R :
Question:
Given below are two statement : 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
Correct Option: 4,
Solution:
Size of ${ }_{97} \mathrm{Bk}^{3+}$ ion is less than that of ${ }_{93} \mathrm{~Np}^{3+}$ due to actinoid contraction.
As we know that in a period from left to right ionic radius decreases and in actinide series it is due to actinoid contraction.