The process requiring absorption of energy is

Options

A. `F rarr F^(-)`
B. `H rarr H^(+)`
C. `Cl rarr Cl^(-)`
D. `O rarr O^(-)`

Answer

To solve the question regarding which process requires the absorption of energy, we will analyze each of the given reactions step by step.

### Step 1: Understand the Types of Reactions
- There are two main types of reactions based on energy changes: **endothermic** and **exothermic**.
- **Endothermic reactions** absorb energy from the surroundings.
- **Exothermic reactions** release energy to the surroundings.

**Hint:** Remember that endothermic reactions require energy input, while exothermic reactions release energy.

### Step 2: Analyze Each Reaction
1. **Reaction 1: Fluorine to Fluorine Negative (F to F⁻)**
- Fluorine (F) has an atomic number of 9 and an electronic configuration of 1s² 2s² 2p⁵.
- When fluorine gains an electron to become F⁻, it achieves a stable configuration (1s² 2s² 2p⁶).
- This process releases energy because forming a stable product from reactants typically releases energy.

**Hint:** Look for stability in products; stable products often mean energy is released.

2. **Reaction 2: Hydrogen to Hydrogen Positive (H to H⁺)**
- Hydrogen (H) has an atomic number of 1.
- When hydrogen loses an electron to become H⁺, energy must be supplied to overcome the attraction between the electron and the nucleus.
- Therefore, this process requires energy input, indicating it is endothermic.

**Hint:** Removing an electron from an atom generally requires energy.

3. **Reaction 3: Chlorine to Chlorine Negative (Cl to Cl⁻)**
- Chlorine (Cl) has an atomic number of 17 and an electronic configuration of 1s² 2s² 2p⁶ 3s² 3p⁵.
- When chlorine gains an electron to become Cl⁻, it also achieves a stable configuration and releases energy.

**Hint:** Again, look for the stability of the product; energy is typically released in these cases.

4. **Reaction 4: Oxygen to Oxygen Negative (O to O²⁻)**
- Oxygen (O) has an atomic number of 8.
- When oxygen gains two electrons to become O²⁻, it becomes more stable and releases energy.

**Hint:** Gaining electrons to achieve stability often results in energy release.

### Step 3: Conclusion
After analyzing all four reactions:
- The only reaction that requires energy absorption is **Reaction 2** (Hydrogen to Hydrogen Positive). This is because energy is needed to remove an electron from hydrogen.

**Final Answer:** The process requiring absorption of energy is **Reaction 2: Hydrogen to Hydrogen Positive (H to H⁺)**.