Which of the following pair consists of only paramagetic species?

Options

A. `H_(2), O_(2)^(+)`
B. `N_(2), O_(2)`
C. CO, `N_(2)`
D. `H_(2)^(+)` , `O_(2)^(-)`

Answer

To determine which of the pairs consists of only paramagnetic species, we need to analyze the electronic configurations of the given molecules and identify whether they have unpaired electrons. Paramagnetic species contain unpaired electrons, while diamagnetic species have all electrons paired.

### Step-by-Step Solution:

1. **Understanding Paramagnetism and Diamagnetism**:
- Paramagnetic species have one or more unpaired electrons.
- Diamagnetic species have all electrons paired.

2. **Analyzing the First Option (H2)**:
- H2 has 2 electrons.
- Its electronic configuration is:
\[ \text{Sigma } 1s^2 \]
- Both electrons are paired, so H2 is **diamagnetic**.

3. **Analyzing the Second Option (O2)**:
- O2 has 16 electrons.
- Its electronic configuration is:
\[ \text{Sigma } 1s^2 \text{ Sigma } 1s^*^2 \text{ Sigma } 2s^2 \text{ Sigma } 2s^*^2 \text{ Sigma } 2p_z^2 \text{ Pi } 2p_x^1 \text{ Pi } 2p_y^1 \]
- O2 has two unpaired electrons in the \( \text{Pi } 2p_x \) and \( \text{Pi } 2p_y \) orbitals, making it **paramagnetic**.

4. **Analyzing the Third Option (N2)**:
- N2 has 14 electrons.
- Its electronic configuration is:
\[ \text{Sigma } 1s^2 \text{ Sigma } 1s^*^2 \text{ Sigma } 2s^2 \text{ Sigma } 2s^*^2 \text{ Sigma } 2p_z^2 \text{ Pi } 2p_x^2 \text{ Pi } 2p_y^2 \]
- All electrons are paired, so N2 is **diamagnetic**.

5. **Analyzing the Fourth Option (H2+ and O2+)**:
- H2+ has 1 electron.
- Its electronic configuration is:
\[ \text{Sigma } 1s^1 \]
- This single electron is unpaired, making H2+ **paramagnetic**.

- O2+ has 15 electrons (one electron removed from O2).
- Its electronic configuration is:
\[ \text{Sigma } 1s^2 \text{ Sigma } 1s^*^2 \text{ Sigma } 2s^2 \text{ Sigma } 2s^*^2 \text{ Sigma } 2p_z^2 \text{ Pi } 2p_x^1 \text{ Pi } 2p_y^0 \]
- O2+ has one unpaired electron in the \( \text{Pi } 2p_x \) orbital, making it **paramagnetic**.

6. **Conclusion**:
- The only pair that consists of only paramagnetic species is the fourth option: **H2+ and O2+**.

### Final Answer:
The correct answer is the fourth option (H2+ and O2+).