Topic: The Periodic Table – Group I Properties
Lesson 1: Physical Properties of Group I Elements
| Section | Details |
|---|---|
| Objective | Describe Group I alkali metals (lithium, sodium, potassium) as relatively soft metals and identify general trends down the group, including: (a) decreasing melting point, (b) increasing density. |
| Activities | – Starter (5 mins): Show a video or images of lithium, sodium, and potassium being cut and ask: “What do you notice about these metals compared to others?”- Main (25 mins): 1. Discuss the softness of Group I metals and relate it to their atomic structure. 2. Explain the trends in melting point and density as you move down the group. 3. Demonstrate a comparison of densities using water (e.g., floating sodium and potassium).- Plenary (10 mins): Students summarize the physical properties of Group I elements in a table. |
| Resources | Videos or images of alkali metals, periodic table, demonstration materials (if feasible), worksheets. |
| Time | 40 minutes total: 5 mins (Starter) + 25 mins (Main) + 10 mins (Plenary). |
| Homework | Research and write about one additional physical property trend of Group I metals. |
| Assessment | Worksheet: Identify and explain trends in melting point and density down Group I. |
| Past Paper Practice | IGCSE Chemistry 0620/41/M/J/20 Q5(a) – Physical properties of Group I elements. |
Lesson 2: Chemical Reactivity of Group I Elements
| Section | Details |
|---|---|
| Objective | Describe the increasing reactivity of lithium, sodium, and potassium as you move down Group I. |
| Activities | – Starter (5 mins): Ask: “Why do some metals react more violently with water than others?”- Main (25 mins): 1. Discuss the trend in reactivity in terms of atomic size, shielding effect, and ease of losing the outer electron. 2. Show or explain the reactions of lithium, sodium, and potassium with water, emphasizing observations (e.g., fizzing, floating, flame for potassium). 3. Write balanced equations for these reactions (e.g., 2Na+2H2O→2NaOH+H2\text{2Na} + 2\text{H}_2\text{O} → 2\text{NaOH} + \text{H}_2).- Plenary (10 mins): Students complete a worksheet predicting the reaction of rubidium with water based on the observed trends. |
| Resources | Videos of reactions with water, safety notes, periodic table, worksheets. |
| Time | 40 minutes total: 5 mins (Starter) + 25 mins (Main) + 10 mins (Plenary). |
| Homework | Write the balanced equation for the reaction of potassium with water and describe the observations. |
| Assessment | Worksheet: Explain why reactivity increases down Group I. |
| Past Paper Practice | IGCSE Chemistry 0620/41/O/N/21 Q5(b) – Trends in reactivity in Group I. |
Lesson 3: Predicting Properties of Other Group I Elements
| Section | Details |
|---|---|
| Objective | Predict the properties of other elements in Group I, given information about the elements. |
| Activities | – Starter (5 mins): Ask: “What do you think rubidium and cesium would look like and how would they behave?”- Main (25 mins): 1. Discuss how trends in Group I elements can be used to predict properties of rubidium and cesium. 2. Predict physical properties (e.g., melting point, density) and chemical behavior (e.g., reaction with water). 3. Compare predictions with data provided in tables or charts.- Plenary (10 mins): Students create a table comparing predicted and actual properties of rubidium and cesium. |
| Resources | Periodic table, data tables for Group I elements, worksheets. |
| Time | 40 minutes total: 5 mins (Starter) + 25 mins (Main) + 10 mins (Plenary). |
| Homework | Research one application of a Group I element and explain how its properties make it suitable for that use. |
| Assessment | Worksheet: Predict the properties of an unknown Group I element based on given trends. |
| Past Paper Practice | IGCSE Chemistry 0620/41/M/J/19 Q4(b) – Predicting properties of Group I elements. |
Key Notes for Students:
- Physical Properties of Group I Metals:
- Soft metals that can be cut with a knife.
- Melting points decrease down the group.
- Densities increase down the group (except for potassium).
- Chemical Properties of Group I Metals:
- Reactivity increases down the group due to larger atomic size and easier loss of the outer electron.
- React with water to form alkalis and hydrogen gas.
- Predicting Properties:
- Trends in Group I can help predict properties of elements lower in the group, such as rubidium and cesium.
Notes for Teachers:
- Use videos or controlled demonstrations for the reactions of Group I metals, emphasizing safety.
- Encourage students to think critically about trends and use these trends to make predictions.
- Provide real-world examples of applications of Group I elements (e.g., lithium in batteries, sodium in streetlights).
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