Lesson Plan

• Describe the four defining features of a homologous series (common functional group, general formula, $-\mathrm{CH}_2$ increment, trend in physical properties).
• Compare how boiling point, melting point, density and solubility change as members increase by one $-\mathrm{CH}_2$ unit.
• Predict the general formula and typical chemical reactions of a series from its functional group.
• Apply a checklist to identify a homologous series in given examples.

• Projector and screen
• Whiteboard and markers
• Printed handouts with the series table and checklist
• Molecular model kits (to add $-\mathrm{CH}_2$ units)
• Worksheet for guided practice
• Interactive quiz platform (e.g., Kahoot) for exit ticket

Begin with a quick “name that functional group” challenge to activate prior knowledge. Explain that today’s focus is on how groups of compounds are linked by systematic structural changes. State that by the end of the lesson students will be able to recognise a homologous series, write its general formula and predict physical‑property trends.

1. Do‑now (5’): Students list common functional groups on a sticky note and share with the class.
2. Mini‑lecture (10’): Define homologous series and present the four key characteristics, using the prepared slide.
3. Guided practice (12’): Using the handout, students fill in the general formula for each series and verify the $-\mathrm{CH}_2$ increment (increase of 14 g mol⁻¹).
4. Demonstration (5’): With model kits, show the stepwise addition of $-\mathrm{CH}_2$ units to methane and discuss the resulting rise in boiling point.
5. Collaborative activity (10’): In groups, learners apply the checklist to a new series (e.g., alcohols) and predict trends in boiling point and solubility.
6. Exit ticket (3’): Individually, students write one characteristic of a homologous series and one predicted physical‑property trend for any series studied.

Recap the four defining features and the observed property trends, linking them back to the functional group. Collect exit tickets to gauge understanding, and assign homework: complete the worksheet’s “real‑world examples” section by researching a homologous series used in industry.