JEE Main202116 Mar 2021Morning ShiftChemistryd and f Block ElementsActual
Given below are two statement : 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 lanthanide contraction. In the light of the above statements, choose the correct answer from the options given below :
Options
- AA is false but R is true
- BBoth A and R are true but R is not the correct explanation of A
- CA is true but R is false
- DBoth A and R are true and R is the correct explanation of A
Correct answer
C. A is true but R is false
Step-by-step solution
Size of Bk 97 3 + ion is less than that of Np 93 3 + due to actinide contraction. As we know that in a period from left to right ionic radius decreases and in actinide series it is due to actinide contraction.