Correct order of electron affinity is/are:

Options

A. `S gt O`
B. `Al gt B`
C. `Mg gt Na`
D. `P gt N`

Answer

To determine the correct order of electron affinity among the given elements, we need to analyze the trends in electron affinity based on the periodic table. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand Electron Affinity
Electron affinity is the amount of energy released when an electron is added to a neutral atom in the gas phase. Generally, elements with higher electron affinity tend to gain electrons more readily.

### Step 2: Analyze the Periodic Trends
1. **Across a Period**: Electron affinity generally increases as you move from left to right across a period due to increasing nuclear charge, which attracts electrons more strongly.
2. **Down a Group**: Electron affinity generally decreases as you move down a group because the atomic size increases, and the added electron is further from the nucleus, resulting in a weaker attraction.

### Step 3: Evaluate Each Given Option
1. **Sulfur (S) > Oxygen (O)**:
- Oxygen has a smaller atomic size and experiences greater inter-electronic repulsion due to its high electron density. Therefore, its electron affinity is less than that of sulfur, making this statement correct.

2. **Aluminum (Al) > Boron (B)**:
- Aluminum is larger than boron, and typically, larger atoms have lower electron affinities. Thus, this statement is incorrect.

3. **Magnesium (Mg) > Sodium (Na)**:
- Magnesium is also larger than sodium, and as a result, it should have a lower electron affinity. Therefore, this statement is incorrect.

4. **Phosphorus (P) > Nitrogen (N)**:
- Similar to oxygen, nitrogen has a smaller atomic size and experiences greater inter-electronic repulsion. Thus, phosphorus has a higher electron affinity than nitrogen, making this statement incorrect.

### Step 4: Conclusion
Based on the analysis:
- The only correct statement is **Sulfur > Oxygen**.
- Therefore, the correct order of electron affinity among the options provided is **Option 1**: Sulfur > Oxygen.

### Final Answer
The correct order of electron affinity is: **Sulfur > Oxygen**.

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