Which of the following compound obey octet rule :

Options

A. `CO_(2)`
B. `SF_(6)`
C. `PCl_(5)`
D. `SO_(3)`

Explanation

To determine which of the given compounds obey the octet rule, we need to analyze the electron configuration of each compound and see if all the atoms in the compound have a total of 8 electrons in their valence shell.

### Step-by-Step Solution:

1. **Understanding the Octet Rule**:
The octet rule states that atoms tend to bond in such a way that they have eight electrons in their valence shell, achieving a noble gas configuration.

2. **Analyzing Each Compound**:
- **Carbon Dioxide (CO2)**:
- Carbon has 4 valence electrons.
- Each oxygen has 6 valence electrons.
- In CO2, carbon forms double bonds with each oxygen atom.
- Total electrons around carbon: 4 (from bonds) + 4 (from double bonds with two oxygens) = 8 electrons.
- Each oxygen has 4 (from bonds) + 4 (from lone pairs) = 8 electrons.
- **Conclusion**: CO2 obeys the octet rule.

- **Sulfur Hexafluoride (SF6)**:
- Sulfur has 6 valence electrons.
- Each fluorine has 7 valence electrons.
- In SF6, sulfur forms single bonds with six fluorine atoms.
- Total electrons around sulfur: 6 (from bonds) + 6 (from six fluorine atoms) = 12 electrons.
- **Conclusion**: SF6 does not obey the octet rule.

- **Phosphorus Pentachloride (PCl5)**:
- Phosphorus has 5 valence electrons.
- Each chlorine has 7 valence electrons.
- In PCl5, phosphorus forms single bonds with five chlorine atoms.
- Total electrons around phosphorus: 5 (from bonds) + 5 (from five chlorine atoms) = 10 electrons.
- **Conclusion**: PCl5 does not obey the octet rule.

- **Sulfur Trioxide (SO3)**:
- Sulfur has 6 valence electrons.
- Each oxygen has 6 valence electrons.
- In SO3, sulfur forms double bonds with three oxygen atoms.
- Total electrons around sulfur: 6 (from bonds) + 6 (from three double bonds) = 12 electrons.
- **Conclusion**: SO3 does not obey the octet rule.

### Final Conclusion:
- The compound that obeys the octet rule is **Carbon Dioxide (CO2)**. The other compounds (SF6, PCl5, SO3) do not obey the octet rule.