Only one lone pair is present on the central atom of 

Options

A. `XeF_2`
B. `XeF_4`
C. `XeO_3`
D. `XeO_4`

Answer

To solve the question regarding which compound has only one lone pair on the central atom, we will analyze each of the given options systematically.

### Step-by-Step Solution:

1. **Identify the Compounds:**
The compounds given are:
- \( \text{XeF}_2 \)
- \( \text{XeF}_4 \)
- \( \text{XeCl}_3 \)
- \( \text{XeO}_4 \)

2. **Determine the Valence Electrons for Xenon:**
Xenon (Xe) is a noble gas and has 8 valence electrons.

3. **Analyze \( \text{XeF}_2 \):**
- **Bond Pairs:** In \( \text{XeF}_2 \), xenon forms 2 bonds with fluorine atoms.
- **Lone Pairs:** The remaining electrons after forming bonds:
- Total electrons = 8
- Electrons used in bonds = 2 (1 for each bond)
- Remaining = 8 - 2 = 6 electrons.
- These 6 electrons form 3 lone pairs.
- **Conclusion:** \( \text{XeF}_2 \) has 3 lone pairs. (Not the answer)

4. **Analyze \( \text{XeF}_4 \):**
- **Bond Pairs:** In \( \text{XeF}_4 \), xenon forms 4 bonds with fluorine atoms.
- **Lone Pairs:**
- Total electrons = 8
- Electrons used in bonds = 4 (1 for each bond)
- Remaining = 8 - 4 = 4 electrons.
- These 4 electrons form 2 lone pairs.
- **Conclusion:** \( \text{XeF}_4 \) has 2 lone pairs. (Not the answer)

5. **Analyze \( \text{XeCl}_3 \):**
- **Bond Pairs:** In \( \text{XeCl}_3 \), xenon forms 3 bonds with chlorine atoms.
- **Lone Pairs:**
- Total electrons = 8
- Electrons used in bonds = 3 (1 for each bond)
- Remaining = 8 - 3 = 5 electrons.
- These 5 electrons consist of 1 lone pair and 2 bond pairs.
- **Conclusion:** \( \text{XeCl}_3 \) has 1 lone pair. (This is a potential answer)

6. **Analyze \( \text{XeO}_4 \):**
- **Bond Pairs:** In \( \text{XeO}_4 \), xenon forms 4 bonds with oxygen atoms.
- **Lone Pairs:**
- Total electrons = 8
- Electrons used in bonds = 4 (1 for each bond)
- Remaining = 8 - 4 = 4 electrons.
- These 4 electrons form 0 lone pairs.
- **Conclusion:** \( \text{XeO}_4 \) has 0 lone pairs. (Not the answer)

7. **Final Conclusion:**
The only compound that has one lone pair on the central atom is \( \text{XeCl}_3 \).

### Answer:
The compound with only one lone pair on the central atom is \( \text{XeCl}_3 \).