In which of the following process maximum energy is released

Options

A. `O_((g))+e^(-) rarr O_((g))^(-)`
B. `S_((g))+e^(-) rarr S_((g))^(-)`
C. `O_((g))^(-) +e^(-) rarr O_((g))^(-2)`
D. `S_((g))^(-)+e^(-) rarr S_((g))^(-2)`

Answer

To determine which process releases the maximum energy, we need to analyze the electron affinity of the given options. Electron affinity is defined as the amount of energy released when an electron is added to a neutral atom in the gas phase. The higher the electron affinity, the more energy is released during the addition of an electron.

### Step-by-Step Solution:

1. **Understand Electron Affinity**:
- Electron affinity is the energy change when an electron is added to a neutral atom. It is usually expressed in kilojoules per mole (kJ/mol). A higher (more negative) value indicates a greater release of energy.

2. **Analyze the Given Options**:
- The options provided involve the addition of electrons to different elements. We need to compare the electron affinities of these elements.

3. **Rule Out Options with High Repulsion**:
- For elements like O (oxygen) and S (sulfur), when an electron is added to O, the resulting O- ion experiences significant electron-electron repulsion due to its smaller size. This repulsion requires energy input, thus reducing the overall energy released.
- Therefore, we can rule out options involving O- and S- as they will not have high electron affinity.

4. **Compare Remaining Options**:
- After ruling out options with high repulsion, we are left with the option that involves sulfur (S). Sulfur is larger than oxygen, which means that the added electron experiences less repulsion.
- Because of this larger atomic size, the addition of an electron to sulfur is easier, and thus, it will have a higher electron affinity compared to oxygen.

5. **Conclusion**:
- The process involving sulfur will release the maximum energy because it has a higher electron affinity compared to oxygen. Therefore, the correct answer is the option that includes sulfur.

### Final Answer:
The process in which maximum energy is released is the addition of an electron to sulfur (S).

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