Lesson Plan

• Describe the structure of alkenes and the nature of the C=C double bond.
• Explain why addition reactions to alkenes produce a single product.
• Identify typical addition reagents and the products formed with ethene.
• Predict the outcome of a simple addition reaction using the planar double‑bond concept.
• Apply the concept by writing balanced equations for hydrogenation and halogenation of alkenes.

• Projector or interactive whiteboard
• PowerPoint slides with diagrams of double bonds and addition mechanisms
• Worksheet with practice reactions
• Molecular model kits (optional)
• Whiteboard markers and chart paper
• Exit ticket cards

Begin with a quick recall question: “What makes alkenes more reactive than alkanes?” Students share answers, linking to the π‑bond. Explain that today they will see why this reactivity leads to a single, predictable product in addition reactions. Success criteria: students will be able to state the single‑product rule and illustrate it with balanced equations.

1. Do‑now (5') – Students list alkene properties on mini‑whiteboards; teacher reviews.
2. Mini‑lecture (10') – Review C=C planar geometry and why addition occurs simultaneously.
3. Demonstration (8') – Show short video of ethene hydrogenation; discuss formation of only ethane.
4. Guided practice (12') – In pairs, use the reagent table to predict products; teacher circulates for misconceptions.
5. Whole‑class discussion (8') – Contrast symmetrical vs unsymmetrical alkenes; reinforce the single‑product rule.
6. Quick quiz (5') – Exit ticket: write the balanced equation for Br₂ addition to propene and explain why only one product forms.

Recap that the planar double bond forces simultaneous addition, guaranteeing one product for simple reagents. Collect exit tickets to check understanding, and assign homework: complete a worksheet predicting products for three additional addition reactions.