The correct order of increasing electron affinity of the following elements is:

Options

A. O lt S lt F lt Cl
B. O lt S lt Cl lt F
C. S lt O lt F lt Cl
D. S lt O lt Cl lt F

Explanation

To determine the correct order of increasing electron affinity for the elements Fluorine (F), Chlorine (Cl), Oxygen (O), and Sulfur (S), we will follow these steps:

### Step 1: Understand Electron Affinity
Electron affinity is defined as the energy change that occurs when an electron is added to a neutral atom to form a negative ion. Generally, higher electron affinity values indicate a greater tendency to gain an electron.

### Step 2: Analyze Periodic Trends
- **Across a Period**: As we move from left to right across a period, electron affinity generally increases due to increasing electronegativity.
- **Down a Group**: As we move down a group, electron affinity typically decreases because the atomic radius increases, making it harder for the nucleus to attract additional electrons.

### Step 3: Compare the Given Elements
1. **Fluorine (F)**: Has a high electron affinity due to its small size and high electronegativity.
2. **Chlorine (Cl)**: Although it is larger than Fluorine, it has a higher electron affinity than Fluorine because it is more stable when gaining an electron.
3. **Oxygen (O)**: Has a high electron affinity but is less than that of Fluorine and Chlorine due to its smaller size, which results in electron-electron repulsion when an additional electron is added.
4. **Sulfur (S)**: Has a lower electron affinity compared to the others due to its larger atomic radius.

### Step 4: Establish the Order
Based on the above analysis, the order of increasing electron affinity is:
- Sulfur (S) < Oxygen (O) < Chlorine (Cl) < Fluorine (F)

### Final Order
The correct order of increasing electron affinity for the elements is:
**Sulfur (S) < Oxygen (O) < Chlorine (Cl) < Fluorine (F)**