For the molecule ethene (C2H4), what is the electron geometry around each carbon atom?

• A. Linear
• B. Trigonal planar
• C. Bent
• D. Tetrahedral

Answer: (B)

Verified step by step guidance

1. Identify the central atom(s) of interest in the molecule, which in this case are the two carbon atoms in ethene (C2H4).
2. Determine the number of regions of electron density (bonding and lone pairs) around each carbon atom. Each carbon in ethene is bonded to two hydrogen atoms and one carbon atom via a double bond.
3. Recall that electron geometry depends on the total number of electron regions around the atom. For each carbon, there are three regions of electron density: two single bonds to hydrogen and one double bond to carbon (counted as one region).
4. Use the VSEPR (Valence Shell Electron Pair Repulsion) theory to predict the electron geometry based on three regions of electron density. According to VSEPR, three regions of electron density arrange themselves in a trigonal planar geometry to minimize repulsion.
5. Conclude that the electron geometry around each carbon atom in ethene is trigonal planar, which corresponds to bond angles of approximately 120 degrees.