The difference between electron gain enthalpies will be maximum between :

Options

A. Ne and F
B. Ar and F
C. Ne and Cl
D. Ar and Cl

Answer

To solve the question regarding the maximum difference in electron gain enthalpies, we will analyze the given options step by step.

### Step 1: Understand Electron Gain Enthalpy
Electron gain enthalpy (ΔEGA) is the amount of energy released when an electron is added to a neutral atom in the gas phase. Generally, this value is negative, indicating that energy is released.

### Step 2: Analyze Trends in Electron Gain Enthalpy
1. **Across a Period**: As we move from left to right across a period, the electron gain enthalpy becomes more negative (more energy is released) due to increasing nuclear charge and decreasing atomic size.
2. **Down a Group**: As we move down a group, the electron gain enthalpy becomes less negative (less energy is released) because the atomic size increases, making it harder for the nucleus to attract an additional electron.

### Step 3: Evaluate the Options
We have four pairs to consider:
1. Neon (Ne) and Fluorine (F)
2. Argon (Ar) and Fluorine (F)
3. Neon (Ne) and Chlorine (Cl)
4. Argon (Ar) and Chlorine (Cl)

#### Option 1: Neon and Fluorine
- Neon has a very high electron gain enthalpy (almost zero) because it is a noble gas and does not tend to gain electrons.
- Fluorine has a high electron gain enthalpy (very negative) because it is a halogen and readily accepts an electron.

#### Option 2: Argon and Fluorine
- Argon, like Neon, has a very high electron gain enthalpy (almost zero).
- Fluorine again has a high electron gain enthalpy (very negative).

#### Option 3: Neon and Chlorine
- Neon has a very high electron gain enthalpy (almost zero).
- Chlorine has a negative electron gain enthalpy but less negative than that of Fluorine.

#### Option 4: Argon and Chlorine
- Argon has a very high electron gain enthalpy (almost zero).
- Chlorine has a negative electron gain enthalpy.

### Step 4: Compare the Differences
- The maximum difference will occur between a noble gas (Ne or Ar) and a halogen (F or Cl).
- Between Neon and Fluorine, and Argon and Fluorine, the difference is significant because one is almost zero and the other is highly negative.
- Between Neon or Argon and Chlorine, the difference is less pronounced than with Fluorine.

### Conclusion
The maximum difference in electron gain enthalpies will be between **Neon and Fluorine** (Option 1) and **Argon and Fluorine** (Option 2). However, since the question asks for the maximum difference, the best choice is **Option 1: Neon and Fluorine**.

### Final Answer
**Option 1: Neon and Fluorine**

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