NEETChemistryd and f Block Elements
Match List-I with List-II. List-I (Ion) List-II (Number of unpaired electrons) (A) La ³⁺ (I) 7 (B) Nd ³⁺ (II) 4 (C) Gd ³⁺ (III) 0 (D) Ho ³⁺ (IV) 3 Choose the correct answer from the options given below:
Options
- A(A)-(III), (B)-(II), (C)-(I), (D)-(IV)
- B(A)-(IV), (B)-(III), (C)-(I), (D)-(II)
- C(A)-(III), (B)-(IV), (C)-(I), (D)-(II)
- D(A)-(III), (B)-(IV), (C)-(II), (D)-(I)
Correct answer
C. (A)-(III), (B)-(IV), (C)-(I), (D)-(II)
Step-by-step solution
The number of unpaired electrons is calculated by writing the electronic configuration of the ions: La (Z = 57) is [ Xe ] 5d¹ 6s² . La ³⁺ is [ Xe ] 4f⁰ . Number of unpaired electrons = 0. Nd (Z = 60) is [ Xe ] 4f⁴ 6s² . Nd ³⁺ is [ Xe ] 4f³ . Number of unpaired electrons = 3. Gd (Z = 64) is [ Xe ] 4f⁷ 5d¹ 6s² . Gd ³⁺ is [ Xe ] 4f⁷ . Number of unpaired electrons = 7. Ho (Z = 67) is [ Xe ] 4f¹¹ 6s² . Ho ³⁺ is [ Xe ] 4f¹⁰ . Number of unpaired electrons = 14 - 10 = 4. Thus, the correct matching is (A)-(III), (B)-(IV), (