Select the endothermic step(s):

Options

A. `S^(-)(g)+e^(-) rarr S^(2-)(g)`
B. `Ne(g)+e^(-) rarr Ne^(-) (g)`
C. `N(g) +e^(-) rarr N^(-)(g)`
D. `AI^(2+)(g) rarr AI^(3+) (g)+e^(-)`

Explanation

To determine the endothermic steps from the given options, we need to analyze each step based on the energy changes involved when electrons are added or removed from atoms or ions. Here is a step-by-step solution:

### Step 1: Understand Endothermic Processes
An endothermic process is one that absorbs energy from the surroundings. This typically occurs when:
- An electron is added to an already negatively charged ion (due to electron-electron repulsion).
- An electron is removed from a cation (since energy is required to overcome the attraction between the nucleus and the electron).

### Step 2: Analyze Each Step
1. **Step 1: Sulfur (S⁻) + e⁻ → S²⁻**
- Sulfur already has a negative charge (S⁻). Adding another electron will face electron-electron repulsion, requiring energy input.
- **Conclusion:** This step is endothermic.

2. **Step 2: Neon (Ne) + e⁻ → Ne⁻**
- Neon is a noble gas with a stable electronic configuration. Adding an electron to a stable configuration makes it unstable, requiring energy.
- **Conclusion:** This step is endothermic.

3. **Step 3: Nitrogen (N) + e⁻ → N⁻**
- Nitrogen is a neutral atom. Adding an electron to a neutral atom typically releases energy (exothermic process).
- **Conclusion:** This step is exothermic.

4. **Step 4: Aluminum (Al³⁺) + e⁻ → Al²⁺**
- Aluminum has already lost two electrons, and removing another electron from the Al²⁺ ion requires energy due to the strong attraction between the nucleus and the remaining electrons.
- **Conclusion:** This step is endothermic.

### Final Conclusion
The endothermic steps are:
- Step 1 (S⁻ + e⁻ → S²⁻)
- Step 2 (Ne + e⁻ → Ne⁻)
- Step 4 (Al³⁺ + e⁻ → Al²⁺)