The hybridization of carbon atoms in a molecule like ethene is determined by drawing the Lewis structure and applying VSEPR theory to count regions of electron density, with hybridized orbitals selected accordingly; ethene's carbon atoms are sp² hybridized.
To determine the hybridization of the carbon atoms in a molecule, such as ethene (C₂H₄), we need to follow these steps:
First, draw the Lewis structure of the molecule.
Consider the number of regions of electron density around each carbon atom using VSEPR theory (Valence Shell Electron Pair Repulsion). Each single bond, double bond, triple bond, or lone pair counts as one region of electron density.
Choose the appropriate set of hybridized orbitals that corresponds to the number of electron density regions observed.
In ethene, each carbon atom has three regions of electron density. There are two single bonds with hydrogen and one double bond with the other carbon atom. Since a double bond is considered as one region of electron density in VSEPR theory, the hybridization would be sp². The geometry around each carbon atom is therefore trigonal planar with approximately 120° bond angles.