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NEETChemistryd and f Block Elements

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

  1. AA is false but R is true
  2. BBoth A and R are true but R is not the correct explanation of A
  3. CA is true but R is false
  4. 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.

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