Correct order of EA is :-

Options

A. `Cl gt O gt N gt C`
B. `Cl gt O gt C gt N`
C. `Cl gt N gt C gt O`
D. `Cl gt C gt O gt N`

Answer

To determine the correct order of electron affinity (EA) among the elements chlorine (Cl), oxygen (O), nitrogen (N), and carbon (C), we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Electron Affinity (EA)**:
- Electron affinity is defined as the energy change that occurs when an electron is added to a neutral gaseous atom. It is a measure of how much an atom wants to gain an electron.

2. **Comparing Periodic Trends**:
- Generally, electron affinity increases across a period from left to right and decreases down a group in the periodic table. This is because elements on the right side of the periodic table (like halogens) are more electronegative and have a greater tendency to gain electrons.

3. **Identifying the Elements**:
- We have the following elements to compare:
- Chlorine (Cl) - Group 17, Period 3
- Oxygen (O) - Group 16, Period 2
- Nitrogen (N) - Group 15, Period 2
- Carbon (C) - Group 14, Period 2

4. **Analyzing Chlorine**:
- Chlorine is a halogen and has a high electron affinity due to its electronegativity and position in the periodic table. It is expected to have the highest electron affinity among the four elements.

5. **Analyzing Oxygen**:
- Oxygen is also highly electronegative and has a significant electron affinity, but it is lower than that of chlorine.

6. **Analyzing Nitrogen and Carbon**:
- For nitrogen, its electron configuration is 1s² 2s² 2p³. When it gains an electron, it becomes 1s² 2s² 2p⁴, which is less stable because it moves from a half-filled p subshell to a more filled one, which is less favorable.
- Carbon has the electron configuration 1s² 2s² 2p². Gaining an electron makes it 1s² 2s² 2p³, which is more stable than nitrogen gaining an electron. Therefore, carbon has a higher electron affinity than nitrogen.

7. **Final Order of Electron Affinity**:
- Based on the above analysis, the order of electron affinity from highest to lowest is:
- Cl > O > C > N

### Conclusion:
The correct order of electron affinity is **Cl > O > C > N**, which corresponds to option B.