Concept: The geometry of a molecule is determined by the arrangement of electron pairs around the central atom, which can be predicted using VSEPR theory. For SF₆, the central sulfur atom is surrounded by six fluorine atoms, leading to an octahedral geometry.

Why (C) is correct:

1. In SF₆, the central sulfur atom is sp³d² hybridized, resulting in an octahedral geometry.

2. An octahedron has 8 faces, 12 edges, and 6 vertices. The central atom (S) is at the center, and the six fluorine atoms (F) are at the vertices.

3. In an ideal octahedral geometry, all bond angles between adjacent S-F bonds are 90°. There are 12 such angles (each F-S-F angle where the two F atoms are adjacent).

4. There are also 3 F-S-F angles of 180° (between F atoms directly opposite each other).

Option Analysis:

• A) 4: This is incorrect. An octahedron has more than 4 angles of 90°.
• B) 8: This is incorrect. While an octahedron has 8 faces, it has 12 angles of 90°.
• C) 12: This is correct. There are 12 F-S-F bond angles of 90° in an octahedral SF₆ molecule.
• D) 16: This is incorrect. There are not 16 angles of 90° in SF₆.

Correct Answer: (C)