In each of the following questions a Statement of Assertion (A ) is given followed by a corresponding statement of Reason (R ) Just below it . Of the statement mark the correct answer as
Assertion . F atom has less negative electron gain enthalpy than C1 atom.
Reason . Additional electrons are repelled more effectively by 3p- electrons in C1 than by 2p- electrons in F atom

Explanation

To solve the question regarding the Assertion and Reason statements, we will analyze both statements step by step.

### Step 1: Analyze the Assertion
- **Assertion (A)**: "F atom has less negative electron gain enthalpy than Cl atom."
- **Understanding**: Electron gain enthalpy refers to the energy change when an electron is added to a neutral atom. A more negative value indicates a greater tendency to gain an electron.
- **Comparison**: Fluorine (F) is smaller in size compared to Chlorine (Cl). Generally, as the size of the atom increases, the electron gain enthalpy becomes less negative (or more positive) because the added electron is further from the nucleus and experiences less attraction.

### Step 2: Analyze the Reason
- **Reason (R)**: "Additional electrons are repelled more effectively by 3p electrons in Cl than by 2p electrons in F."
- **Understanding**: The reason suggests that the repulsion experienced by the added electron is greater in Chlorine due to the presence of 3p electrons compared to the 2p electrons in Fluorine.
- **Implication**: This repulsion in Chlorine makes it less favorable for the atom to gain an additional electron, leading to a less negative electron gain enthalpy.

### Step 3: Conclusion
- **Combining A and R**: The assertion states that Fluorine has less negative electron gain enthalpy than Chlorine, which is true. The reason provided explains why this is the case, indicating that the repulsion from the 3p electrons in Chlorine is greater than that from the 2p electrons in Fluorine.
- **Final Answer**: Both the Assertion and Reason are correct, and the Reason correctly explains the Assertion.

### Final Answer:
Both Assertion and Reason are correct, and the Reason explains the Assertion.

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