Amongst the following statements, which is/are correct?

Options

A. Electronegtaivity of sulphur is greater than that of oxygen
B. Electron affinity of oxygen is smaller than that of sulphur.
C. Electron gain enthalpy of fluorine is most negative
D. Electron gain enthalpy of chlorine is most negative

Answer

To determine which statements are correct regarding electronegativity, electron affinity, and electron gain enthalpy, let's analyze each statement step by step.

### Step 1: Analyze the first statement
**Statement 1:** "Electronegativity of sulphur is greater than that of oxygen."

- **Explanation:** Electronegativity is the ability of an atom to attract electrons in a chemical bond. In the periodic table, electronegativity generally increases from left to right across a period and decreases from top to bottom within a group. Oxygen is located above sulfur in Group 16 of the periodic table. Therefore, oxygen has a higher electronegativity than sulfur.
- **Conclusion:** This statement is **incorrect**.

### Step 2: Analyze the second statement
**Statement 2:** "Electron affinity of oxygen is smaller than that of sulphur."

- **Explanation:** Electron affinity is the amount of energy released when an electron is added to a neutral atom. Generally, smaller atoms have a higher electron affinity because they can better attract additional electrons due to their effective nuclear charge. Oxygen, being smaller than sulfur, has a higher electron affinity than sulfur.
- **Conclusion:** This statement is **incorrect**.

### Step 3: Analyze the third statement
**Statement 3:** "Electron gain enthalpy of chlorine is most negative."

- **Explanation:** Electron gain enthalpy refers to the energy change when an electron is added to a neutral atom in the gas phase. Chlorine has a very high tendency to gain an electron due to its high electronegativity and its position in the periodic table. When chlorine gains an electron, it achieves a stable noble gas configuration (similar to argon), which makes the process highly exothermic, resulting in a very negative electron gain enthalpy.
- **Conclusion:** This statement is **correct**.

### Step 4: Analyze the fourth statement
**Statement 4:** "Electron affinity is defined as releasing of energy to add the electron to an element."

- **Explanation:** This statement is a definition of electron affinity. It correctly describes the process where energy is released when an electron is added to an atom. However, it is important to clarify that while the process is exothermic (releases energy), the magnitude of the electron affinity can vary among different elements.
- **Conclusion:** This statement is **correct**.

### Final Conclusion
The correct statements from the given options are:
- Statement 3: "Electron gain enthalpy of chlorine is most negative."
- Statement 4: "Electron affinity is defined as releasing of energy to add the electron to an element."

### Summary of Correct Statements:
- B and D are correct.