Which of the following statement is correct?

Options

A. The magnitude of the second electron ffinity of sulphur is greater than that of oxygen
B. The magnitude of the second electron affinity of sulphur is less than that of oxygen
C. the first electron affinities of bromine and iodine are approximately the same
D. The first electron affinity of fluorine is greater than that of chlorine

Answer

To determine which statement is correct regarding electron affinity and electron gain enthalpy, we will analyze each option step by step.

### Step 1: Understanding Electron Affinity and Electron Gain Enthalpy
- **Electron Affinity** is the energy change when an electron is added to a neutral atom to form a negative ion.
- **Electron Gain Enthalpy** is the enthalpy change associated with the addition of an electron to a gaseous atom.

### Step 2: Evaluate Each Statement
1. **Statement A**: The magnitude of second electron gain enthalpy of sulfur is greater than that of oxygen.
- **Analysis**: The second electron gain enthalpy is generally more negative (greater in magnitude) for elements with smaller atomic size because they can stabilize the added electron better. Oxygen has a smaller atomic size than sulfur, thus it can stabilize the added electron more effectively. Therefore, this statement is **incorrect**.

2. **Statement B**: The magnitude of second electron gain enthalpy of sulfur is less than that of oxygen.
- **Analysis**: As discussed, oxygen's smaller size allows it to have a more negative (greater in magnitude) second electron gain enthalpy compared to sulfur. Thus, this statement is **correct**.

3. **Statement C**: The first electron affinity of bromine and iodine are approximately the same.
- **Analysis**: As we move down the group in the periodic table, electron affinity generally decreases due to increased atomic size and shielding effect. Therefore, this statement is **incorrect**.

4. **Statement D**: The first electron affinity of fluorine is greater than that of chlorine.
- **Analysis**: Although fluorine is smaller than chlorine, it experiences significant inter-electronic repulsion in its small size, making its electron affinity less negative than that of chlorine. Thus, this statement is **incorrect**.

### Conclusion
After analyzing all the statements, the only correct statement is **Statement B**: The magnitude of second electron gain enthalpy of sulfur is less than that of oxygen.