Concept: Hybridization

Hybridization is the concept of mixing atomic orbitals to form new hybrid orbitals suitable for the pairing of electrons to form chemical bonds in valence bond theory. The type of hybridization determines the geometry and bond angles around the central atom.

Why (B) is correct:

When one s-orbital and one p-orbital hybridize, they form two new equivalent hybrid orbitals called sp hybrid orbitals. These two sp hybrid orbitals are oriented at an angle of $180^{\circ }$ to each other, resulting in a linear geometry. This arrangement minimizes electron-electron repulsion between the hybrid orbitals.

Option Analysis:

• A) Two mutual perpendicular orbitals: This describes the orientation of unhybridized p-orbitals (px, py, pz) but not sp hybrid orbitals.
• B) Two orbitals at $180^{\circ }$: This is the correct description for sp hybridization, leading to a linear geometry.
• C) Four orbitals in tetrahedral directions: This describes $s{p}^3$ hybridization, where one s-orbital and three p-orbitals mix to form four $s{p}^3$ hybrid orbitals oriented at $109.5^{\circ }$ to each other.
• D) Three orbitals in the same plane: This describes $s{p}^2$ hybridization, where one s-orbital and two p-orbitals mix to form three $s{p}^2$ hybrid orbitals oriented at $120^{\circ }$ to each other in a trigonal planar geometry.

Correct Answer: (B)