The element with highest electron affinity will belong to

Options

A. Period 2 , group 17
B. Period 3, group 17
C. Period 2, group 18
D. Period 2, group 1

Answer

To determine the element with the highest electron affinity, we need to analyze the periodic trends and the characteristics of the elements in the relevant groups and periods.

### Step-by-Step Solution:

1. **Understanding Electron Affinity**:
- Electron affinity is defined as the amount of energy released when an electron is added to a neutral atom in the gaseous state to form a negative ion.

2. **Identify Relevant Groups and Periods**:
- The question asks about the element with the highest electron affinity. We should focus on elements in Group 17 (halogens) as they are known for having high electron affinities.

3. **List Elements in Relevant Groups and Periods**:
- For Period 2: The relevant element is Fluorine (F).
- For Period 3: The relevant element is Chlorine (Cl).

4. **Analyze Electron Affinity Trends**:
- Generally, electron affinity increases across a period from left to right and decreases down a group.
- In Group 17, Fluorine is smaller in size compared to Chlorine, which might suggest it has a higher electron affinity. However, due to the increased electron-electron repulsion in the smaller Fluorine atom when an additional electron is added, its electron affinity is actually lower than that of Chlorine.

5. **Conclusion**:
- Chlorine (Cl), which is in Period 3 and Group 17, has a higher electron affinity than Fluorine (F) because it can accommodate an additional electron more easily without significant repulsion.

6. **Final Answer**:
- The element with the highest electron affinity belongs to Period 3, Group 17 (Chlorine).