Which one of the following species is diamagnetic in nature ?

Options

A. `He_(2)^(+)`
B. `H_(2)`
C. `H_(2)^(+)`
D. `H_(2)^(-)`

Explanation

To determine which of the given species is diamagnetic, we need to analyze the electron configurations of each species and check for the presence of unpaired electrons. A species is considered diamagnetic if all its electrons are paired, while it is paramagnetic if there are unpaired electrons.

### Step-by-Step Solution:

1. **Identify the Species**: The species we need to analyze are He2⁺, H2, H2⁺, and H2⁻.

2. **Analyze He2⁺**:
- **Number of Electrons**: Helium (He) has 2 electrons. In He2⁺, we remove one electron, resulting in a total of 3 electrons.
- **Electron Configuration**: The configuration is σ1s² (2 electrons) and σ*1s¹ (1 electron).
- **Unpaired Electrons**: There is 1 unpaired electron in σ*1s¹.
- **Conclusion**: He2⁺ is **paramagnetic**.

3. **Analyze H2**:
- **Number of Electrons**: H2 has 2 hydrogen atoms, each contributing 1 electron, totaling 2 electrons.
- **Electron Configuration**: The configuration is σ1s².
- **Unpaired Electrons**: There are 0 unpaired electrons since both electrons are paired.
- **Conclusion**: H2 is **diamagnetic**.

4. **Analyze H2⁺**:
- **Number of Electrons**: H2⁺ has 1 less electron than H2, resulting in 1 electron.
- **Electron Configuration**: The configuration is σ1s¹.
- **Unpaired Electrons**: There is 1 unpaired electron.
- **Conclusion**: H2⁺ is **paramagnetic**.

5. **Analyze H2⁻**:
- **Number of Electrons**: H2⁻ has 1 extra electron compared to H2, resulting in 3 electrons.
- **Electron Configuration**: The configuration is σ1s² and σ*1s¹.
- **Unpaired Electrons**: There is 1 unpaired electron.
- **Conclusion**: H2⁻ is **paramagnetic**.

### Final Conclusion:
Among the species analyzed, the only species that is **diamagnetic** is **H2**.