Assertion: Electron gain enthalpy always becomes less negative as we go down a group in Modern periodic table.
Reason: The size of the atom increase on going down the group in Modern periodic table and the added electron would be farther from the nucleus.

Options

A. Assertion is correct statement and reason is wrong statement.
B. Assertion and reason both are correct statements and reason is correct explanation of Assertion.
C. Assertion and reason both are wrong statements.
D. Assertion and wrong statements and reason is correct statements.

Explanation

### Step-by-Step Solution:

1. **Define Electron Gain Enthalpy**:
- Electron gain enthalpy is defined as the amount of energy released or required when an electron is added to a neutral atom in the gaseous state. It can be exothermic (negative value) when energy is released or endothermic (positive value) when energy is required.

2. **Trend of Electron Gain Enthalpy in the Periodic Table**:
- As we move down a group in the periodic table, the electron gain enthalpy becomes less negative. This means that it is becoming less exothermic, indicating that it requires more energy to add an electron.

3. **Reason for the Trend**:
- The reason for this trend is that the atomic size increases as we move down a group. The added electron is farther from the nucleus due to the increase in the number of electron shells.

4. **Effect of Atomic Size on Electron Attraction**:
- With the nucleus being farther away from the outermost electron shell, the attractive force between the nucleus (which is positively charged) and the added electron (which is negatively charged) decreases. This results in a lower tendency for the atom to gain an electron.

5. **Conclusion**:
- Both the assertion that electron gain enthalpy becomes less negative down a group and the reason that atomic size increases, making the added electron farther from the nucleus, are true. The reason correctly explains the assertion.

### Final Answer:
Both the assertion and reason are true, and the reason is the correct explanation of the assertion.

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