Metals and Non-metals: Properties and Reactions
Learning Outcomes
- Differentiate between metals and non-metals based on physical and chemical properties
- Explain the reactivity series of metals and predict displacement reactions
- Describe the formation and properties of ionic compounds
- Understand the extraction processes for different metals based on their reactivity
- Explain corrosion and methods to prevent it
- Understand the importance of alloys in daily life
Starter Questions
- Why are electric wires made of copper but the handles are plastic?
- Why do gold and silver not corrode like iron?
- Why is sodium stored in kerosene?
- How can we prevent iron from rusting?
- Why are alloys more useful than pure metals?
Key Concepts & Activities
1. Physical Properties of Metals and Non-metals
Comparison of physical properties:
| Property | Metals | Non-metals |
|---|---|---|
| Lustre | Shiny (metallic lustre) | Dull (except iodine) |
| Malleability | Can be hammered into sheets | Brittle |
| Ductility | Can be drawn into wires | Non-ductile |
| Conductivity | Good conductors of heat and electricity | Poor conductors (except graphite) |
| State at room temp | Mostly solids (except Hg) | Solids, liquids or gases |
| Sonority | Produce ringing sound | Do not produce sound |
Activity 1: Test samples of metals and non-metals for malleability, conductivity and other physical properties.
2. Chemical Reactions of Metals
Reactions with different substances:
| Reaction | Equation | Observation | Example |
|---|---|---|---|
| With Oxygen | Metal + O2 → Metal oxide | Forms oxide layer | 4Na + O2 → 2Na2O |
| With Water | Metal + H2O → Metal hydroxide + H2 | Vigorous to no reaction | 2K + 2H2O → 2KOH + H2 |
| With Acids | Metal + Acid → Salt + H2 | Effervescence | Zn + 2HCl → ZnCl2 + H2 |
| With Salt Solutions | Metal A + Salt of Metal B → Metal B + Salt of Metal A | Displacement | Fe + CuSO4 → Cu + FeSO4 |
Activity 2: Perform displacement reactions and observe reactivity trends.
3. Reactivity Series and Extraction Methods
Reactivity series and corresponding extraction methods:
| Metal | Reactivity | Occurrence | Extraction Method |
|---|---|---|---|
| K, Na, Ca, Mg, Al | High | Compounds | Electrolysis |
| Zn, Fe, Pb, Cu | Medium | Oxides/Sulphides | Reduction with carbon |
| Hg, Ag, Au | Low | Native state | Heating alone |
Activity 3: Simulate extraction processes for different metals.
4. Ionic Compounds and Corrosion
Properties of ionic compounds:
| Property | Explanation | Example |
|---|---|---|
| Physical State | Solid at room temperature | NaCl crystals |
| Melting/Boiling Point | High due to strong ionic bonds | NaCl melts at 801°C |
| Solubility | Soluble in water, insoluble in organic solvents | NaCl dissolves in water |
| Conductivity | Conduct in molten/aqueous state | Molten NaCl conducts |
Activity 4: Test conductivity of ionic compounds in solid and molten states.
Period Wise Plan
Total Duration: 8 Periods (45 minutes each)
Period 1: Introduction to Metals and Non-metals
Key Topics: Classification, physical properties, daily life uses
Activities:
- Classify common elements as metals/non-metals
- Test samples for lustre, malleability, conductivity
- Discuss why certain materials are used for specific purposes
Resources: Metal and non-metal samples, conductivity tester
Period 2: Chemical Properties of Metals
Key Topics: Reactions with oxygen, water, acids
Activities:
- Observe reactions of Na, Mg, Zn, Fe with water/acid
- Compare reactivity of different metals
- Write balanced chemical equations
Resources: Metal samples, acid solutions, safety equipment
Period 3: Reactivity Series
Key Topics: Displacement reactions, activity series
Activities:
- Perform displacement reactions (Fe + CuSO4, etc.)
- Arrange metals in order of reactivity
- Predict reaction outcomes
Resources: Salt solutions, metal strips, observation charts
Period 4: Formation of Ionic Compounds
Key Topics: Electron transfer, properties of ionic compounds
Activities:
- Model formation of NaCl, MgO
- Test conductivity of ionic compounds
- Compare melting points
Resources: Electron dot diagrams, conductivity apparatus
Period 5: Extraction of Metals
Key Topics: Metallurgy, enrichment, extraction methods
Activities:
- Flowchart of extraction processes
- Simulate roasting and calcination
- Discuss electrolytic refining
Resources: Metallurgy charts, ore samples
Period 6: Corrosion and Prevention
Key Topics: Rusting, factors affecting corrosion, prevention
Activities:
- Experiment on conditions for rusting
- Compare prevention methods
- Case study: Iron pillar of Delhi
Resources: Iron nails, test tubes, oil, anhydrous CaCl2
Period 7: Alloys and Their Importance
Key Topics: Purpose of alloying, common alloys, properties
Activities:
- Compare properties of alloys vs pure metals
- Research common alloys and uses
- Discuss amalgams
Resources: Alloy samples, property comparison charts
Period 8: Review & Assessment
Key Topics: Comprehensive review, concept clarification
Activities:
- Reactivity series quiz
- Problem-solving exercises
- Written and practical assessments
Resources: Assessment sheets, reaction prediction cards
Teaching Strategies
Assessment Timeline
Formative: Ongoing through periods 1-7 (lab reports, quizzes, participation)
Summative: Period 8 (comprehensive test, practical assessment, concept application)
Assessment
Formative Assessment
- Observation during experiments and group work
- Short quizzes on properties and reactions
- Lab reports on displacement reactions
- Concept maps of reactivity series
Summative Assessment
- Written exam covering all concepts
- Practical test on identifying metals/non-metals
- Predicting reaction outcomes
- Explaining extraction methods
Extended Learning
- Research project on metallurgy in ancient India
- Designing corrosion prevention methods
- Debate on uses of metals vs non-metals
- Creating models of ionic compounds
Frequently Asked Questions
- Why is sodium stored in kerosene?
- Sodium is highly reactive with oxygen and moisture in air. Storing it in kerosene prevents contact with air and prevents violent reactions that could cause fires.
- Why do gold and silver not corrode like iron?
- Gold and silver are low in the reactivity series and don't readily react with oxygen or moisture. Iron is more reactive and forms iron oxide (rust) when exposed to moist air.
- What determines if a metal will displace another in a reaction?
- A metal can displace another metal from its compound only if it is more reactive (higher in the reactivity series). For example, zinc can displace copper from copper sulfate solution because zinc is more reactive than copper.
- Why are alloys more useful than pure metals?
- Alloys combine the properties of different metals to create materials with improved characteristics like greater strength, resistance to corrosion, or lower melting points than pure metals.
- Why can ionic compounds conduct electricity when molten but not when solid?
- In solid state, ions are fixed in position and can't move. When molten or dissolved, the ions become mobile and can carry electric current.
