Identify the hybridization state and geometry of each carbon atom in benzene. Use that information to determine the geometry of the entire molecule:
The Correct Answer and Explanation is:
Correct Answer:
Each carbon atom in benzene is sp² hybridized and has trigonal planar geometry. The overall geometry of the benzene molecule is planar hexagonal (a flat, regular six-sided ring).
Explanation
Benzene (C₆H₆) is a well-known aromatic compound composed of six carbon atoms arranged in a ring. Each carbon atom in the ring is bonded to two other carbon atoms and one hydrogen atom. Understanding the hybridization of the carbon atoms helps determine the geometry of the molecule.
In benzene, each carbon atom forms three sigma (σ) bonds — two with adjacent carbon atoms and one with a hydrogen atom. To form these three sigma bonds, each carbon atom uses sp² hybrid orbitals, which are made by combining one s orbital and two p orbitals from the carbon atom. This leaves one unhybridized p orbital on each carbon.
These sp² hybrid orbitals are arranged in a trigonal planar geometry, with bond angles of approximately 120 degrees. The unhybridized p orbitals on each carbon atom are perpendicular to the plane of the ring and overlap sideways with p orbitals on adjacent carbon atoms. This sideways overlap creates a continuous π (pi) electron cloud above and below the ring, resulting in delocalized electrons that are shared by all six carbon atoms. This delocalization is responsible for benzene’s stability and aromatic character.
Because all six carbon atoms are sp² hybridized and lie in the same plane, the entire benzene molecule is flat and planar. The carbon-carbon bond lengths in benzene are all equal, approximately 1.39 angstroms, which is between a single and double bond length due to the delocalized π bonding.
In conclusion, each carbon in benzene is sp² hybridized with trigonal planar geometry, and the overall molecule forms a planar hexagonal shape with delocalized electrons providing extra stability.
