Lesson Plan

• Describe how atomic radius, ionisation energy, electronegativity and metallic character change down a group.
• Explain the reasons for each trend using electron‑shell structure and shielding.
• Apply group trends to predict reactivity and physical properties of elements in Groups 1, 2, 17 and 18.
• Analyse sample questions and justify predictions using periodic trends.

• Projector and screen
• Printed periodic‑table handouts (highlighting Groups 1, 2, 17, 18)
• Worksheet with trend tables and sample questions
• Element cards (e.g., Li, Na, K, Mg, Ca, Cl, Br)
• Whiteboard and markers
• Exit‑ticket slips

Begin by asking students to predict which alkali metal reacts most vigorously with water and why. Review the concept of valence electrons and the layout of periods and groups in the periodic table. Explain that by the end of the lesson they will be able to state the direction of key trends down a group and use them to justify predictions.

1. Do‑now (5') – Quick written response to the water‑reactivity question; collect answers.
2. Mini‑lecture (10') – Define a group, show the trend table, and illustrate reasons with a diagram on the projector.
3. Guided practice (15') – Students fill in a blank trend chart in pairs, discussing the underlying reasons.
4. Group activity (15') – Using element cards, each group predicts atomic radius, ionisation energy, electronegativity and metallic character for a given element and shares reasoning.
5. Sample‑question solving (10') – Individually answer the three provided questions; then peer‑check and discuss answers.
6. Check for understanding (5') – Exit ticket: list two trends and give a real‑world example for each.

Recap the four main trends observed down a group and how they relate to electron configuration. Collect exit tickets to gauge understanding, and assign the worksheet on Groups 3 and 4 as homework to extend the practice of trend analysis.