In which one of the following compounds does the central atom obey the octet rule ?

Options

A. `XeF_(4)`
B. `XeOF_(2)`
C. `SCl_(2)`
D. `AlCl_(3)`

Explanation

To determine which compound has a central atom that obeys the octet rule, we will analyze each of the given compounds step-by-step.

### Step 1: Analyze the first compound, XeF4
1. **Identify the central atom**: Xenon (Xe).
2. **Count the valence electrons**:
- Xenon has 8 valence electrons.
- Each fluorine (F) contributes 1 electron, and there are 4 fluorine atoms, contributing a total of 4 electrons.
- Total = 8 (from Xe) + 4 (from F) = 12 electrons.
3. **Determine the electron arrangement**:
- The structure is square planar with 2 lone pairs on Xe.
4. **Conclusion**: The central atom (Xe) has 12 electrons, which does not obey the octet rule.

### Step 2: Analyze the second compound, XeOF2
1. **Identify the central atom**: Xenon (Xe).
2. **Count the valence electrons**:
- Xenon has 8 valence electrons.
- Oxygen (O) contributes 2 electrons, and there are 2 fluorine atoms contributing 2 electrons (1 each).
- Total = 8 (from Xe) + 2 (from O) + 2 (from F) = 12 electrons.
3. **Determine the electron arrangement**:
- The structure has 2 lone pairs and 3 bond pairs.
4. **Conclusion**: The central atom (Xe) has 12 electrons, which does not obey the octet rule.

### Step 3: Analyze the third compound, SCl2
1. **Identify the central atom**: Sulfur (S).
2. **Count the valence electrons**:
- Sulfur has 6 valence electrons.
- Each chlorine (Cl) contributes 1 electron, and there are 2 chlorine atoms, contributing a total of 2 electrons.
- Total = 6 (from S) + 2 (from Cl) = 8 electrons.
3. **Determine the electron arrangement**:
- The structure has 2 lone pairs and 2 bond pairs.
4. **Conclusion**: The central atom (S) has 8 electrons, which obeys the octet rule.

### Step 4: Analyze the fourth compound, AlCl3
1. **Identify the central atom**: Aluminum (Al).
2. **Count the valence electrons**:
- Aluminum has 3 valence electrons.
- Each chlorine (Cl) contributes 1 electron, and there are 3 chlorine atoms, contributing a total of 3 electrons.
- Total = 3 (from Al) + 3 (from Cl) = 6 electrons.
3. **Determine the electron arrangement**:
- The structure has 0 lone pairs and 3 bond pairs.
4. **Conclusion**: The central atom (Al) has 6 electrons, which does not obey the octet rule.

### Final Conclusion
Among the compounds analyzed, only **SCl2** has a central atom (sulfur) that obeys the octet rule.