Determine the molecular geometry about each interior atom and draw each molecule. (Skeletal structure is indicated in parentheses.)
a. C₂H₂ (skeletal structure HCCH)
b. C₂H₄ (skeletal structure H₂CCH₂)
c. C₂H₆ (skeletal structure H₃CCH₃)

Key Concepts

VSEPR Theory

Valence Shell Electron Pair Repulsion (VSEPR) Theory is a model used to predict the geometry of individual molecules based on the repulsion between electron pairs in the valence shell of the central atom. According to VSEPR, electron pairs will arrange themselves as far apart as possible to minimize repulsion, leading to specific molecular shapes such as linear, trigonal planar, or tetrahedral.

Hybridization

Hybridization is the concept of mixing atomic orbitals to form new hybrid orbitals that can accommodate the bonding requirements of a molecule. For example, in ethyne (C2H2), the carbon atoms undergo sp hybridization, resulting in a linear geometry, while in ethylene (C2H4), sp2 hybridization leads to a trigonal planar arrangement around each carbon atom.

Molecular Geometry

Molecular geometry refers to the three-dimensional arrangement of atoms within a molecule. It is determined by the number of bonding pairs and lone pairs of electrons around the central atom. Understanding molecular geometry is crucial for predicting the physical and chemical properties of substances, including reactivity and polarity.