Highest electron affinity observe in :-

Options

A. `2s^(2)2p^(5)`
B. `2s^(2)2p^(4)`
C. `2s^(2)2p^(3)`
D. `2s^(2)2p^(1)`

Answer

To determine which element has the highest electron affinity among the given options, we will analyze the electron configurations and the corresponding atomic numbers of each element.

### Step-by-Step Solution:

1. **Identify the Elements from Their Electron Configurations:**
- The first option is \(1s^2 2s^2 2p^5\):
- Atomic number = 9 (Element: Fluorine)
- The second option is \(1s^2 2s^2 2p^4\):
- Atomic number = 8 (Element: Oxygen)
- The third option is \(1s^2 2s^2 2p^3\):
- Atomic number = 7 (Element: Nitrogen)
- The fourth option is \(1s^2 2s^2 2p^1\):
- Atomic number = 5 (Element: Boron)

2. **Determine the Group of Each Element:**
- Fluorine (F) is in Group 17 (Halogens).
- Oxygen (O) is in Group 16 (Chalcogens).
- Nitrogen (N) is in Group 15 (Pnictogens).
- Boron (B) is in Group 13 (Boron group).

3. **Understand the Trend in Electron Affinity:**
- Electron affinity generally increases as you move from left to right across a period in the periodic table. This is due to the increasing effective nuclear charge, which attracts additional electrons more strongly.
- Among the elements listed, Fluorine, being a halogen, is expected to have the highest electron affinity because halogens have a strong tendency to gain an electron to achieve a stable noble gas configuration.

4. **Compare the Electron Affinities:**
- Fluorine has the highest electron affinity due to its position in Group 17 and its ability to gain an electron to complete its outer shell.
- Oxygen has a lower electron affinity than Fluorine, and Nitrogen and Boron have even lower values.

5. **Conclusion:**
- Therefore, the element with the highest electron affinity among the given options is **Fluorine (F)**.

### Final Answer:
The highest electron affinity is observed in **Fluorine (F)**.