Chapter 4: Materials - Metals and Non-Metals

Introduction to Materials

• Familiar materials: iron, aluminum, copper.
• Table 4.1: Appearance and hardness of materials (iron, coal, sulfur, aluminum, copper).
• Distinction: Metals vs non-metals based on physical and chemical properties.
• Physical Properties: Luster and hardness.

Physical Properties of Metals and Non-Metals

Activity 4.1: Beating Materials

• Observe changes in shape upon beating iron, coal, aluminum, and pencil lead.
  • Iron and Aluminum: Malleable, can form sheets.
  • Coal and Pencil Lead: Brittle, break without shape change.

Malleability

• Definition: Ability to be beaten into thin sheets (characteristic of metals).
• Examples: Silver foil, aluminum foil.

Conductivity

• Experiment with Heat: Metal pans conduct heat; plastic/wood handles protect from heat.
• Activity 4.2: Electric Circuit Test.
  • Metals (iron, copper) are good conductors.
  • Non-metals (coal, sulfur) are poor conductors.

Ductility

• Definition: Ability to be drawn into wires.
• Examples: Aluminum and copper wires.

Sonority

• Observation: Metals produce ringing sound when struck.
• Examples: Metal coins, bells.

Summary of Properties

• Metals: Hard, lustrous, malleable, ductile, sonorous, conductors of heat/electricity.
• Non-Metals: Soft, dull, brittle, non-sonorous, poor conductors.

Chemical Properties of Metals and Non-Metals

Reaction with Oxygen

• Rusting: Iron forming oxide with oxygen and water.
• Magnesium Burning: Forms basic oxide.
• Activity 4.3: Nature of rust tested with litmus paper.

Copper Reaction

• Observation: Greenish deposit on copper due to reaction with moist air.
• Chemical Reaction: Copper forms hydroxide and carbonate.

Non-Metal Oxides

• Activity 4.4: Sulfur burning forms sulfur dioxide, which is acidic.

Reaction with Water

• Sodium: Reacts vigorously with water, stored in kerosene.
• Phosphorus: Stored in water to avoid contact with air.

Reaction with Acids and Bases

Metals and Acids

• Activity 4.5: Test reactions with hydrochloric and sulfuric acid.
  • Metals react with acids to produce hydrogen gas.

Bases

• Activity 4.7: Metals react with sodium hydroxide to produce hydrogen gas.

Displacement Reactions

• Activity 4.8: Observing displacement reactions with copper sulfate, zinc, iron.
• Reactivity Series: More reactive metals displace less reactive ones.

Uses of Metals and Non-Metals

• Metals: Machinery, vehicles, utensils.
• Non-Metals: Breathing, fertilizers, purification, antiseptics, fireworks.

Elements and Atoms

• Element Definition: Cannot be broken down further.
• Atoms: Smallest unit of element.
• Chemical Reaction: Formation of new substances.

Exercises and Questions

• Various exercises to reinforce learning about metals and non-metals.

Extended Learning Activities

• Suggested experiments and projects to explore the properties and uses of metals and non-metals further.

Keywords

• List of important terms: atom, conductor, ductility, malleability, sonora, reactivity, etc.

End of Chapter 4

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Additional Notes

• Exceptions: Sodium and potassium (soft, cut with a knife), mercury (liquid at room temperature).
• Important Reactions: Understanding the reaction equations and why they occur as they do.
• Further Exploration: Various activities and projects to deepen understanding of material properties.