To determine which of the given species is paramagnetic, we need to analyze the electron configuration of each species and check for unpaired electrons. A species is considered paramagnetic if it has unpaired electrons, while it is diamagnetic if all electrons are paired.
### Step-by-Step Solution:
1. **Identify the species**: The species we need to analyze are:
- N-O positive (NO⁺)
- O₂ negative (O₂⁻)
- C-N negative (CN⁻)
- CO
2. **Calculate the total number of electrons for each species**:
- **NO⁺**: Nitrogen (N) has 7 electrons and Oxygen (O) has 8 electrons. The positive charge indicates the loss of one electron.
- Total electrons = 7 + 8 - 1 = 14 electrons.
- **O₂⁻**: Each Oxygen has 8 electrons, and with one additional negative charge, we have:
- Total electrons = 8 + 8 + 1 = 17 electrons.
- **CN⁻**: Carbon (C) has 6 electrons and Nitrogen (N) has 7 electrons. The negative charge indicates the gain of one electron.
- Total electrons = 6 + 7 + 1 = 14 electrons.
- **CO**: Carbon (C) has 6 electrons and Oxygen (O) has 8 electrons.
- Total electrons = 6 + 8 = 14 electrons.
3. **Determine the electron configuration using Molecular Orbital Theory (MOT)**:
- **NO⁺ (14 electrons)**:
- Electron configuration: σ1s², σ1s*², σ2s², σ2s*², σ2p_z², π2p_x² = π2p_y², π*2p_x¹, π*2p_y¹ (all paired).
- Result: All electrons are paired → Diamagnetic.
- **O₂⁻ (17 electrons)**:
- Electron configuration: σ1s², σ1s*², σ2s², σ2s*², σ2p_z², π2p_x² = π2p_y², π*2p_x¹ (one unpaired).
- Result: One unpaired electron → Paramagnetic.
- **CN⁻ (14 electrons)**:
- Electron configuration: σ1s², σ1s*², σ2s², σ2s*², π2p_x² = π2p_y² (all paired).
- Result: All electrons are paired → Diamagnetic.
- **CO (14 electrons)**:
- Electron configuration: σ1s², σ1s*², σ2s², σ2s*², σ2p_z², π2p_x² = π2p_y² (all paired).
- Result: All electrons are paired → Diamagnetic.
4. **Conclusion**: From the analysis, the only species that is paramagnetic is **O₂⁻**.
### Final Answer:
**O₂⁻ is paramagnetic.**
