Medium MCQ +4 / -1 PYQ · JEE Mains 2021

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 :

  1. A Both A and B are true and R is the correct explanation of A
  2. B A is false but R is true
  3. C A is true but R is false Correct answer
  4. D Both A and B are true but R is not the correct explanation of A

Solution

Size of Bk<sup>3+</sup> is 98 pm<br><br> Size of Np<sup>3+</sup> is 101 pm<br><br> So size of Np<sup>3+</sup> is more than Bk3+ ion.<br><br> there is a gradual decrease in the size of M<sup>3+</sup> ions across the series. This may be referred to as the actinoid contraction.

About this question

Subject: Chemistry · Chapter: d and f Block Elements · Topic: Properties of Transition Metals

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