| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Chemistry |
| Lesson Topic: Define structural isomers and illustrate with $C_4H_{10}$ and $C_4H_{8}$ examples |
Learning Objective/s:
- Describe what structural (constitutional) isomers are and why they have different properties.
- Identify and draw the structural formulas for the isomers of $C_4H_{10}$ and $C_4H_{8}$.
- Explain how experimental observations (e.g., boiling point, IR spectra) can be used to distinguish isomers.
- Apply the concept of isomerism to predict properties of simple alkanes and alkenes.
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Materials Needed:
- Projector or interactive whiteboard
- PowerPoint/Google Slides with skeletal diagrams
- Printed worksheet with drawing space and quick‑check questions
- Model kits (ball‑and‑stick) for building $C_4$ isomers
- Exit‑ticket slips
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Introduction:
Begin with a short video clip showing two liquids that look similar but behave differently, prompting the question “Why do they act so differently?” Connect to prior knowledge of molecular formulas and ask students to recall the formula for butane. State that by the end of the lesson they will be able to recognise and draw structural isomers and explain their property differences.
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Lesson Structure:
- Do‑Now (5′): Write the molecular formula $C_4H_{10}$ and list any compounds they already know with that formula.
- Mini‑lecture (10′): Define structural isomers, show LaTeX‑rendered formulas for n‑butane and isobutane, and discuss why connectivity matters.
- Guided Practice (12′): Using the model kits, students build the two $C_4H_{10}$ isomers, then sketch them on the worksheet.
- Extension to Alkenes (8′): Briefly present $C_4H_{8}$ isomers (1‑butene, cis‑2‑butene, trans‑2‑butene) with skeletal drawings.
- Concept Check (5′): Quick‑check questions from the source (e.g., “How would you distinguish 1‑butene from 2‑butene experimentally?”) answered via think‑pair‑share.
- Formative Assessment (5′): Exit ticket – write one structural isomer of $C_4H_{10}$ and one key property difference between the two isomers.
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Conclusion:
Recap the definition of structural isomers and the examples covered, emphasizing the link between structure and physical/chemical properties. Collect exit tickets to gauge understanding and assign a short homework task: draw any two structural isomers for $C_5H_{12}$ and note one property that would differ.
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