Expanded octet is present in

Options

A. `SF_(6)`
B. `PCl_(5)`
C. `IF_(7)`
D. All of these

Answer

To determine which compounds exhibit an expanded octet, we need to analyze the valence electrons of the central atom in each compound. An expanded octet occurs when a central atom has more than 8 valence electrons in its outer shell.

### Step-by-Step Solution:

1. **Understanding Expanded Octet**:
- An expanded octet refers to a situation where the central atom in a molecule has more than 8 electrons in its valence shell. This typically occurs in elements from the third period and beyond, which can utilize d-orbitals for bonding.

2. **Analyzing SF6**:
- **Structure**: SF6 (sulfur hexafluoride) has a central sulfur atom surrounded by six fluorine atoms.
- **Valence Electrons**: Each bond between sulfur and fluorine consists of 2 electrons. Since there are 6 bonds, the total number of electrons around sulfur is:
\[ 6 \text{ bonds} \times 2 \text{ electrons/bond} = 12 \text{ electrons} \]
- **Conclusion**: Sulfur in SF6 has 12 valence electrons, which is greater than 8, indicating an expanded octet.

3. **Analyzing PCl5**:
- **Structure**: PCl5 (phosphorus pentachloride) has a central phosphorus atom surrounded by five chlorine atoms.
- **Valence Electrons**: Each bond consists of 2 electrons. Therefore, for PCl5:
\[ 5 \text{ bonds} \times 2 \text{ electrons/bond} = 10 \text{ electrons} \]
- **Conclusion**: Phosphorus in PCl5 has 10 valence electrons, which is also greater than 8, indicating an expanded octet.

4. **Analyzing IF7**:
- **Structure**: IF7 (iodine heptafluoride) has a central iodine atom surrounded by seven fluorine atoms.
- **Valence Electrons**: Each bond consists of 2 electrons. Thus, for IF7:
\[ 7 \text{ bonds} \times 2 \text{ electrons/bond} = 14 \text{ electrons} \]
- **Conclusion**: Iodine in IF7 has 14 valence electrons, which is significantly greater than 8, indicating an expanded octet.

5. **Final Conclusion**:
- Since all three compounds (SF6, PCl5, and IF7) exhibit an expanded octet, the correct answer to the question is that expanded octet is present in all of these compounds.

### Final Answer:
Expanded octet is present in SF6, PCl5, and IF7. Therefore, the correct option is "all of these."