The one with lowest electron affinity in group 16 is

Options

A. Oxygen
B. Sulphur
C. Selenium
D. Tellurium

Answer

To determine which element in Group 16 has the lowest electron affinity, we will analyze the trend in electron affinity as we move down the group and consider the specific properties of the elements involved.

### Step-by-Step Solution:

1. **Understanding Electron Affinity**:
- Electron affinity is the energy change that occurs when an electron is added to a neutral atom in the gas phase. A more negative value indicates a greater tendency to gain an electron.

2. **Group 16 Elements**:
- The elements in Group 16 (the chalcogens) include Oxygen (O), Sulfur (S), Selenium (Se), and Tellurium (Te).

3. **Trend in Electron Affinity**:
- Generally, as we move down a group in the periodic table, the electron affinity decreases. This is due to the increase in atomic size and the corresponding increase in electron shielding, which reduces the effective nuclear charge felt by the added electron.

4. **Comparing the Elements**:
- Oxygen is at the top of the group, followed by Sulfur, Selenium, and Tellurium at the bottom.
- Although the trend suggests that electron affinity decreases down the group, Oxygen is unique due to its small size and high electronegativity.

5. **Electron Repulsion in Oxygen**:
- Oxygen has a small atomic radius, which leads to significant electron-electron repulsion when an additional electron is added. This repulsion makes it less favorable for oxygen to gain an electron compared to the larger atoms in the group.

6. **Conclusion**:
- Despite the general trend, Oxygen has the lowest electron affinity among the Group 16 elements due to the high electron-electron repulsion in its small atomic structure.

### Final Answer:
The element with the lowest electron affinity in Group 16 is **Oxygen (O)**.