Concept: Molecular geometry is determined by the number of electron domains (bonding pairs and lone pairs) around the central atom, as predicted by VSEPR theory. The hybridization of the central atom is also related to its geometry.

Why (B) is correct:

• CCl₄: Carbon (C) is the central atom. It has 4 valence electrons. It forms 4 single bonds with 4 chlorine (Cl) atoms. There are no lone pairs on the central carbon atom. Thus, there are 4 bonding pairs and 0 lone pairs, leading to a steric number of 4. According to VSEPR theory, a molecule with 4 bonding pairs and 0 lone pairs has a tetrahedral geometry and sp³ hybridization.

Option Analysis:

• A) SF₄: Sulfur (S) is the central atom. It has 6 valence electrons. It forms 4 single bonds with 4 fluorine (F) atoms and has 1 lone pair. This gives a steric number of 5 (4 bonding pairs + 1 lone pair), resulting in a see-saw geometry (derived from trigonal bipyramidal electron geometry).
• C) XeF₄: Xenon (Xe) is the central atom. It has 8 valence electrons. It forms 4 single bonds with 4 fluorine (F) atoms and has 2 lone pairs. This gives a steric number of 6 (4 bonding pairs + 2 lone pairs), resulting in a square planar geometry (derived from octahedral electron geometry).
• D) All of these: As SF₄ and XeF₄ are not tetrahedral, this option is incorrect.

Correct Answer: (B)