Question

Match List-I with List-II:

List-I ( Ions )		List-II ( No. of unpaired electrons )
A	Zn$^{2+}$	(I)	0
B	Cu$^{2+}$	(II)	4
C	Ni$^{2+}$	(III)	1
D	Fe$^{2+}$	(IV)	2

Choose the correct answer from the options given below:

• A. (A)-(I), (B)-(II), (C)-(III), (D)-(IV)
• B. (A)-(I), (B)-(III), (C)-(II), (D)-(IV)
• C. (A)-(I), (B)-(III), (C)-(IV), (D)-(II)
• D. (A)-(III), (B)-(IV), (C)-(I), (D)-(II)

Answer 1

The Correct Option is C

The key to solving this problem is to determine the number of unpaired electrons for the given ions. Below is the detailed explanation and matching of List-I with List-II: 

1. Zn$^{2+}$: Zinc's atomic number is 30, with an electron configuration of [Ar] 3d¹⁰ 4s². Zn$^{2+}$ loses two electrons, resulting in a configuration of [Ar] 3d¹⁰. Since all electrons in 3d are paired, 0 unpaired electrons. Match: (I).
2. Cu$^{2+}$: Copper has an atomic number of 29 with a configuration of [Ar] 3d¹⁰ 4s¹. In Cu$^{2+}$, it loses two electrons, resulting in [Ar] 3d⁹. There is one unpaired electron in the 3d orbital. Match: (III).
3. Ni$^{2+}$: Nickel has an atomic number of 28, with a configuration of [Ar] 3d⁸ 4s². In Ni$^{2+}$, it loses two electrons, leading to [Ar] 3d⁸. It has two unpaired electrons. Match: (IV).
4. Fe$^{2+}$: Iron has an atomic number of 26 with a configuration of [Ar] 3d⁶ 4s². Fe$^{2+}$ loses two electrons, resulting in [Ar] 3d⁶, with four unpaired electrons. Match: (II).

Based on the above analysis, the correct matches are: (A)-(I), (B)-(III), (C)-(IV), (D)-(II).

Answer 2

1. Zn²⁺: Electron configuration of Zn is [Ar] 3d¹⁰. The ion has 0 unpaired electrons. Therefore, (A) - (I).

2. Cu²⁺: Electron configuration of Cu is [Ar] 3d¹⁰ 4s¹. The ion has 1 unpaired electron after losing 2 electrons. Therefore, (B) - (III).

3. Ni²⁺: Electron configuration of Ni is [Ar] 3d⁸ 4s². The ion has 2 unpaired electrons. Therefore, (C) - (IV).

4. Fe²⁺: Electron configuration of Fe is [Ar] 3d⁶ 4s². The ion has 4 unpaired electrons. Therefore, (D) - (II).

Thus, the correct matches are: (A) - (I), (B) - (III), (C) - (IV), (D) - (II).