Which of the following is paramagnetic as well as coloured ion ?

Options

A. `Cu^(+)`
B. `Cu^(2+)`
C. `Sc^(3+)`
D. `Zn^(2+)`

Answer

To determine which of the following ions is both paramagnetic and colored, we need to analyze the electronic configurations of the given ions and check for the presence of unpaired electrons.

### Step-by-Step Solution:

1. **Understand Paramagnetism and Color**:
- Paramagnetic substances have unpaired electrons. The presence of unpaired electrons is what makes an ion paramagnetic.
- The color of transition metal compounds is often due to the presence of unpaired electrons in d-orbitals, which can absorb visible light.

2. **Analyze Copper (Cu) Ions**:
- **Cu⁺ (Copper(I))**:
- Atomic number = 29
- Electronic configuration = [Ar] 3d¹⁰ 4s¹
- When Cu loses one electron to form Cu⁺, it loses the 4s electron:
- Cu⁺ configuration = [Ar] 3d¹⁰
- Unpaired electrons = 0 (fully filled d-orbitals)
- Therefore, Cu⁺ is not paramagnetic and not colored.

- **Cu²⁺ (Copper(II))**:
- Atomic number = 29
- Electronic configuration = [Ar] 3d¹⁰ 4s¹
- When Cu loses two electrons to form Cu²⁺, it loses the 4s electron and one 3d electron:
- Cu²⁺ configuration = [Ar] 3d⁹
- Unpaired electrons = 1 (one unpaired electron in 3d)
- Therefore, Cu²⁺ is paramagnetic and colored.

3. **Analyze Scandium (Sc) Ions**:
- **Sc³⁺ (Scandium(III))**:
- Atomic number = 21
- Electronic configuration = [Ar] 3d¹ 4s²
- When Sc loses three electrons to form Sc³⁺, it loses all three (2 from 4s and 1 from 3d):
- Sc³⁺ configuration = [Ar] 3d⁰
- Unpaired electrons = 0 (no unpaired electrons)
- Therefore, Sc³⁺ is not paramagnetic and not colored.

4. **Analyze Zinc (Zn) Ions**:
- **Zn²⁺ (Zinc(II))**:
- Atomic number = 30
- Electronic configuration = [Ar] 3d¹⁰ 4s²
- When Zn loses two electrons to form Zn²⁺, it loses the 4s electrons:
- Zn²⁺ configuration = [Ar] 3d¹⁰
- Unpaired electrons = 0 (fully filled d-orbitals)
- Therefore, Zn²⁺ is not paramagnetic and not colored.

5. **Conclusion**:
- The only ion that is both paramagnetic and colored is **Cu²⁺**.

### Final Answer:
**Cu²⁺ (Copper(II)) is the paramagnetic and colored ion.**