NCERT Notes: Grade 10 Science - Chapter 3: Metals and Non-metals

Introduction

Our Earth comprises a myriad of elements, primarily classified as metals and non-metals. Their unique properties define their uses in various industries, from electronics to construction.

1. Physical Properties

Metals:

• Luster: Metals have a shiny surface.
• Malleability: They can be beaten into thin sheets.
• Ductility: Can be drawn into wires.
• Conductivity: Good conductors of heat and electricity.
• Density and Melting Point: Generally high.

Non-metals:

• Lack metallic luster; can be dull or shiny.
• Brittle, not malleable or ductile.
• Poor conductors, with exceptions like graphite.
• Generally low density and melting point.

2. Chemical Properties

Metals:

• Reaction with Oxygen: Form metal oxides. E.g., (2Cu + O_2 → 2CuO).
• Reaction with Water: Produce metal hydroxides and hydrogen gas.
• Reaction with Acids: Produce salt and hydrogen gas. E.g., (2Na + 2HCl → 2NaCl + H_2).
• Displacement Reactions: A more reactive metal can replace a less reactive metal from its salt solution.

Non-metals:

• Form acidic or neutral oxides with oxygen.
• Generally non-reactive with water.
• React with bases to form salt and water.

3. Uses of Metals and Non-metals

Metals:

• Iron: Used in construction due to its strength.
• Copper and Aluminum: Used in electrical cables due to conductivity.
• Gold and Silver: Used in jewelry due to luster and malleability.

Non-metals:

• Oxygen: Essential for respiration.
• Carbon: As coal, it’s a primary fuel; as diamond, it’s a precious gem.
• Silicon: Used in computer chips.
• Nitrogen: Used in fertilizers.

4. Environmental Impact

• Mining: Extracting metals from ores affects the environment. Mining sites are prone to erosion, leading to environmental degradation.
• Refining: Can lead to water and air pollution if not managed properly.

5. Corrosion and Prevention

• Metals react with substances around them and wear away. E.g., Rusting of iron.
• Preventive measures:
  • Galvanization: Coating with zinc.
  • Alloying: Mixing two metals to improve resistance.

6. Alloys

• Mixtures of metals that possess properties of its constituent metals.
• Brass: Copper and Zinc.
• Bronze: Copper and Tin.
• Improve strength, durability, and resistance to corrosion.

Conclusion

The distinction between metals and non-metals lies at the foundation of numerous industries and innovations. Recognizing their properties, uses, and the environmental implications of their extraction and use is crucial for sustainable progress.

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Reference: NCERT Grade 10 Science - Chapter 3: Metals and Non-metals

Note: This article is an SEO-optimized summary focusing on metals and non-metals, their characteristics, reactions, uses, and more. Students should refer to the original NCERT textbook for detailed explanations, illustrations, and experiments.