01 Structure
Alkenes are unsaturated open-chain hydrocarbons containing at least one C=C double bond. The double bond consists of one strong sigma (σ) bond and one weaker pi (π) bond, which is easily broken — this is why alkenes are much more reactive than alkanes. They may be considered alkanes minus two hydrogen atoms; general formula CₙH₂ₙ (n ≥ 2).