Electron affinity of the elements or ions shown correctly?

Options

A. `S gt O^(-)`
B. `P gt N^(-)`
C. `O^(-) gt S^(-)`
D. `N^(-) gt P`

Answer

To determine the correct statements regarding the electron affinity of the elements or ions mentioned, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Electron Affinity**:
- Electron affinity is defined as the energy change that occurs when an electron is added to a neutral atom in the gas phase. A higher electron affinity indicates a greater ability to gain an electron.

2. **Comparing Sulfur (S) and Oxygen Ion (O⁻)**:
- Sulfur (S) has a higher electron affinity than the oxygen ion (O⁻). This is because oxygen is smaller in size and already has a negative charge. Adding another electron to O⁻ (to form O²⁻) is endothermic (requires energy) due to electron-electron repulsion. In contrast, adding an electron to sulfur (to form S⁻) is exothermic (releases energy).

**Conclusion**: Electron affinity of S > Electron affinity of O⁻.

3. **Comparing Phosphorus (P) and Nitrogen Ion (N⁻)**:
- Phosphorus (P) has a higher electron affinity than the nitrogen ion (N⁻). Nitrogen is also small and already has a negative charge. Adding another electron to N⁻ (to form N²⁻) is unfavorable due to repulsion between the two negative charges. In contrast, phosphorus can easily gain an electron.

**Conclusion**: Electron affinity of P > Electron affinity of N⁻.

4. **Comparing Oxygen Ion (O⁻) and Sulfur Ion (S⁻)**:
- Between O⁻ and S⁻, even though both have negative charges, O⁻ is smaller and experiences greater repulsion when trying to gain another electron. Therefore, the electron affinity of O⁻ is less than that of S⁻.

**Conclusion**: Electron affinity of O⁻ < Electron affinity of S⁻.

5. **Comparing Nitrogen Ion (N⁻) and Phosphorus (P)**:
- This comparison is similar to the previous one. Since N⁻ has a negative charge and is small, it will repel an additional electron more than phosphorus would. Thus, phosphorus has a higher electron affinity.

**Conclusion**: Electron affinity of P > Electron affinity of N⁻.

### Final Summary:
- The correct statements regarding the electron affinities are:
1. Electron affinity of S > Electron affinity of O⁻.
2. Electron affinity of P > Electron affinity of N⁻.
3. Electron affinity of O⁻ < Electron affinity of S⁻.
4. Electron affinity of P > Electron affinity of N⁻.