The number of paramagentic species among the following is
`O_(2), CO, N_(2), C_(2), CsO_(2), BaO_(2), CO_(2)`

Answer

To determine the number of paramagnetic species among the given molecules, we need to analyze each molecule for the presence of unpaired electrons. A species is considered paramagnetic if it has at least one unpaired electron.

### Step-by-Step Solution:

1. **O₂ (Oxygen)**:
- Total electrons: 16 (8 from each O atom).
- Molecular Orbital Configuration:
- σ(1s)² σ*(1s)² σ(2s)² σ*(2s)² σ(2p_z)² (paired) π(2p_x)² π(2p_y)² (paired) π*(2p_x)¹ π*(2p_y)¹ (unpaired).
- Unpaired Electrons: 2.
- **Conclusion**: O₂ is paramagnetic.

2. **CO (Carbon Monoxide)**:
- Total electrons: 14 (6 from C and 8 from O).
- Molecular Orbital Configuration:
- σ(1s)² σ*(1s)² σ(2s)² σ*(2s)² σ(2p_z)² (paired) π(2p_x)² π(2p_y)² (paired).
- Unpaired Electrons: 0.
- **Conclusion**: CO is diamagnetic.

3. **N₂ (Nitrogen)**:
- Total electrons: 14 (7 from each N atom).
- Molecular Orbital Configuration:
- σ(1s)² σ*(1s)² σ(2s)² σ*(2s)² σ(2p_z)² (paired) π(2p_x)² π(2p_y)² (paired).
- Unpaired Electrons: 0.
- **Conclusion**: N₂ is diamagnetic.

4. **C₂ (Dicarbon)**:
- Total electrons: 12 (6 from each C atom).
- Molecular Orbital Configuration:
- σ(1s)² σ*(1s)² σ(2s)² σ*(2s)² σ(2p_z)² (paired) π(2p_x)² π(2p_y)² (paired).
- Unpaired Electrons: 0.
- **Conclusion**: C₂ is diamagnetic.

5. **CsO₂ (Cesium Peroxide)**:
- Total electrons: 18 (1 from Cs, 12 from O₂).
- The outermost electrons from Cs are paired, and O₂ contributes 2 unpaired electrons.
- Unpaired Electrons: 1 (from O₂).
- **Conclusion**: CsO₂ is paramagnetic.

6. **BaO₂ (Barium Peroxide)**:
- Total electrons: 20 (2 from Ba, 12 from O₂).
- The outermost electrons from Ba are paired, and O₂ contributes 2 unpaired electrons.
- Unpaired Electrons: 0.
- **Conclusion**: BaO₂ is diamagnetic.

7. **CO₂ (Carbon Dioxide)**:
- Total electrons: 16 (4 from C and 12 from O).
- Molecular Orbital Configuration:
- σ(1s)² σ*(1s)² σ(2s)² σ*(2s)² σ(2p_z)² (paired) π(2p_x)² π(2p_y)² (paired).
- Unpaired Electrons: 0.
- **Conclusion**: CO₂ is diamagnetic.

### Summary of Findings:
- Paramagnetic Species: O₂, CsO₂
- Diamagnetic Species: CO, N₂, C₂, BaO₂, CO₂

### Final Answer:
The number of paramagnetic species among the given options is **2** (O₂ and CsO₂).

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