NEETChemistryd and f Block Elements
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): The Eu ²⁺ ion (Z = 63) is strongly paramagnetic with a spin-only magnetic moment of approximately 7.9 BM. Reason (R): The Eu ²⁺ ion is formed by the loss of two electrons from the 4 f subshell of the Europium atom. In the light of the above statements, choose the correct answer from the options giv
Options
- ABoth (A) and (R) are true and (R) is the correct explanation of (A)
- BBoth (A) and (R) are true but (R) is not the correct explanation of (A)
- C(A) is true but (R) is false
- D(A) is false but (R) is true
Correct answer
C. (A) is true but (R) is false
Step-by-step solution
The electronic configuration of the Europium atom (Z = 63) is [ Xe ] 4 f ^7 6 s ^2 . The Eu ²⁺ ion is formed by the loss of two electrons from the outermost 6 s subshell, not the 4 f subshell. Therefore, Reason (R) is false. The electronic configuration of Eu ²⁺ is [ Xe ] 4 f ^7 . It has 7 unpaired electrons. The spin-only magnetic moment ( ) is calculated as: = n(n+2) BM = 7(7+2) = 63 7.9 BM Thus, Assertion (A) is true. Answer: (A) is true but (R) is false