Which of the following molecules has more than one lone pair ?

Options

A. `SO_(2)`
B. `XeF_(2)`
C. `SiF_(4)`
D. `CH_(4)`

Answer

To determine which of the given molecules has more than one lone pair, we will analyze each molecule's structure and calculate the steric number to find out the hybridization and the number of lone pairs.

### Step-by-Step Solution:

1. **Identify the Molecules**: The molecules we need to analyze are SO2, XeF2, SiF4, and CH4.

2. **Calculate the Steric Number for SO2**:
- **Valence Electrons**: Sulfur (S) has 6 valence electrons, and each oxygen (O) has 6 valence electrons.
- **Formula**: Steric Number = 1/2 × (Number of Valence Electrons + Number of Monovalent Atoms - Cationic Charge + Anionic Charge)
- **Calculation**:
- Valence Electrons: 6 (S) + 6 (O) + 6 (O) = 18
- Monovalent Atoms: 0
- Charge: 0
- Steric Number = 1/2 × (18) = 9/2 = 3
- **Hybridization**: sp2
- **Lone Pairs**: SO2 has one lone pair on sulfur.

3. **Calculate the Steric Number for XeF2**:
- **Valence Electrons**: Xenon (Xe) has 8 valence electrons, and each fluorine (F) has 7 valence electrons.
- **Calculation**:
- Valence Electrons: 8 (Xe) + 7 (F) + 7 (F) = 22
- Monovalent Atoms: 2 (F)
- Charge: 0
- Steric Number = 1/2 × (22) = 11
- **Hybridization**: sp3d
- **Lone Pairs**: XeF2 has three lone pairs on xenon.

4. **Calculate the Steric Number for SiF4**:
- **Valence Electrons**: Silicon (Si) has 4 valence electrons, and each fluorine (F) has 7 valence electrons.
- **Calculation**:
- Valence Electrons: 4 (Si) + 7 (F) + 7 (F) + 7 (F) + 7 (F) = 32
- Monovalent Atoms: 4 (F)
- Charge: 0
- Steric Number = 1/2 × (32) = 16
- **Hybridization**: sp3
- **Lone Pairs**: SiF4 has no lone pairs.

5. **Calculate the Steric Number for CH4**:
- **Valence Electrons**: Carbon (C) has 4 valence electrons, and each hydrogen (H) has 1 valence electron.
- **Calculation**:
- Valence Electrons: 4 (C) + 1 (H) + 1 (H) + 1 (H) + 1 (H) = 8
- Monovalent Atoms: 4 (H)
- Charge: 0
- Steric Number = 1/2 × (8) = 4
- **Hybridization**: sp3
- **Lone Pairs**: CH4 has no lone pairs.

6. **Conclusion**:
- SO2 has 1 lone pair.
- XeF2 has 3 lone pairs.
- SiF4 has 0 lone pairs.
- CH4 has 0 lone pairs.
- Therefore, the molecule that has more than one lone pair is **XeF2**.

### Final Answer:
**XeF2** has more than one lone pair.