Covalent bond: orbital overlap, sigma and pi bonds
Chemical Bonding (Basics) · Chemistry
Study notes
Explain the bonding in ethene (C₂H₄) using sigma and pi bonds. Step 1: Each C forms 3 sigma bonds (2 C–H + 1 C–C) in a plane. Step 2: One unhybridised p orbital remains on each C, sideways overlap → 1 pi bond. Step 3: C=C is 1σ + 1π; total per molecule: 5σ + 1π. Step 4: The pi bond locks rotation — hence cis/trans isomers exist. Breaking the pi bond (easier than sigma) is how addition reactions start.