The electron gain enthalpies of halogens decrease in the order `F gt CI gt Br gt I`. Comment upon the statement

Explanation

To comment on the statement regarding the electron gain enthalpies of halogens decreasing in the order \( F > Cl > Br > I \), we need to analyze the concept of electron gain enthalpy and the factors affecting it.

### Step-by-Step Solution:

1. **Understanding Electron Gain Enthalpy**:
- Electron gain enthalpy is defined as the amount of energy released when an electron is added to a neutral atom in the gaseous state. A more negative value indicates a greater tendency to gain an electron.

2. **Trends in Halogens**:
- Halogens belong to Group 17 of the periodic table. The elements in this group include Fluorine (F), Chlorine (Cl), Bromine (Br), and Iodine (I).
- As we move down the group from F to I, the atomic size increases due to the addition of electron shells.

3. **Expected Trend**:
- Generally, as atomic size increases, the attraction between the nucleus and the added electron decreases, leading to less negative electron gain enthalpy. Thus, we would expect the order to be \( F < Cl < Br < I \) in terms of electron gain enthalpy.

4. **Analyzing Fluorine**:
- Despite being the smallest atom, Fluorine has a unique situation. The small size leads to significant inter-electronic repulsion when an additional electron is added to its already compact 2p orbital.
- This repulsion makes the addition of an electron less favorable, resulting in a less negative electron gain enthalpy compared to Chlorine.

5. **Correct Order**:
- Therefore, the correct order of electron gain enthalpies for halogens is actually \( Cl > F > Br > I \). Chlorine has a more favorable electron gain enthalpy than Fluorine due to the reasons mentioned above.

6. **Conclusion**:
- The statement that the electron gain enthalpies of halogens decrease in the order \( F > Cl > Br > I \) is incorrect. The correct order is \( Cl > F > Br > I \).