JEE MainChemistryp Block Elements (Group 15, 16, 17 & 18)
SF ₆ is a known, stable compound, whereas OF ₆ does not exist. The primary chemical reason for this difference is:
Options
- AOxygen is highly electronegative and cannot share six electrons with fluorine.
- BOxygen has a very small atomic size, leading to extreme steric hindrance among six fluorine atoms.
- COxygen does not have vacant d-orbitals in its valence shell to expand its octet.
- DSulfur has a higher ionization enthalpy than oxygen, allowing it to form more bonds.
Correct answer
C. Oxygen does not have vacant d-orbitals in its valence shell to expand its octet.
Step-by-step solution
Oxygen is a Period 2 element and its valence shell ( n=2 ) contains only 2s and 2p orbitals. Due to the absence of vacant d-orbitals, oxygen cannot expand its covalency beyond 4. Therefore, it cannot form 6 bonds to form OF ₆ . Sulfur, being a Period 3 element, possesses vacant 3d orbitals in its valence shell, allowing it to expand its octet and form SF ₆ . Answer: Oxygen does not have vacant d-orbitals in its valence shell to expand its octet.