The species which is paramagnetic

Options

A. `Cr^(+)`
B. `Zn^(2+)`
C. `Cu^(+)`
D. `MnO_(4)^(-2)`

Answer

To determine which species is paramagnetic among the given options, we need to analyze the electronic configurations of each species and check for the presence of unpaired electrons. Paramagnetic species have unpaired electrons, while diamagnetic species have all paired electrons.

### Step-by-Step Solution:

1. **Identify the Species**: The options provided are:
- A) Chromium ion (Cr⁺)
- B) Zinc ion (Zn²⁺)
- C) Copper ion (Cu⁺)
- D) Permanganate ion (MnO₄²⁻)

2. **Analyze Chromium Ion (Cr⁺)**:
- Atomic number of Chromium (Cr) = 24.
- Ground state electronic configuration: Ar (18) 3d⁵ 4s¹.
- For Cr⁺, one electron is removed: Configuration becomes Ar 3d⁵.
- In 3d⁵, all five electrons are unpaired.
- **Conclusion**: Cr⁺ is paramagnetic.

3. **Analyze Zinc Ion (Zn²⁺)**:
- Atomic number of Zinc (Zn) = 30.
- Ground state electronic configuration: Ar (18) 3d¹⁰ 4s².
- For Zn²⁺, two electrons are removed: Configuration becomes Ar 3d¹⁰.
- In 3d¹⁰, all ten electrons are paired.
- **Conclusion**: Zn²⁺ is diamagnetic.

4. **Analyze Copper Ion (Cu⁺)**:
- Atomic number of Copper (Cu) = 29.
- Ground state electronic configuration: Ar (18) 3d¹⁰ 4s¹.
- For Cu⁺, one electron is removed: Configuration becomes Ar 3d¹⁰.
- In 3d¹⁰, all ten electrons are paired.
- **Conclusion**: Cu⁺ is diamagnetic.

5. **Analyze Permanganate Ion (MnO₄²⁻)**:
- Determine the oxidation state of Manganese (Mn) in MnO₄²⁻.
- Let oxidation state of Mn = X.
- Oxygen has an oxidation state of -2, and there are four oxygen atoms: 4(-2) = -8.
- The overall charge is -2: X - 8 = -2 → X = +6.
- Atomic number of Manganese (Mn) = 25.
- Ground state electronic configuration: Ar (18) 3d⁵ 4s².
- For Mn⁺⁶, six electrons are removed: Configuration becomes 3d¹.
- In 3d¹, there is one unpaired electron.
- **Conclusion**: MnO₄²⁻ is paramagnetic.

### Final Conclusion:
The species that are paramagnetic are:
- A) Chromium ion (Cr⁺)
- D) Permanganate ion (MnO₄²⁻)