📘Class 10 Science – Chapter: Metals and Non-Metals Notes

🔹 Introduction

• Elements are classified as metals and non-metals based on their physical and chemical properties.

• Metals are electropositive elements, while non-metals are electronegative.

🔹 Physical Properties

Example: Copper is a good conductor of electricity.

🔹 Chemical Properties of Metals

1. Reaction with Oxygen:

   • Metals form metal oxides.

   • Metal + O₂ → Metal oxide

   • Example: 4Na + O₂ → 2Na₂O

2. Reaction with Water:

   • Forms metal hydroxide and hydrogen gas.

   • Example: 2K + 2H₂O → 2KOH + H₂ ↑

3. Reaction with Acids:

   • Produces salt and hydrogen gas.

   • Example: Zn + 2HCl → ZnCl₂ + H₂ ↑

4. Reaction with Other Metal Salts (Displacement Reaction):

   • More reactive metal displaces less reactive metal.

   • Example: Fe + CuSO₄ → FeSO₄ + Cu

🔹 Chemical Properties of Non-Metals

1. Reaction with Oxygen:

   • Non-metals form acidic or neutral oxides.

   • Example: C + O₂ → CO₂

2. Reaction with Water:

   • Generally, non-metals do not react with water.

3. Reaction with Acids:

   • Non-metals usually do not react with acids.

4. Reaction with Chlorine:

   • Forms covalent chlorides.

   • Example: H₂ + Cl₂ → 2HCl

🔹 Reactivity Series of Metals

• Arrangement of metals in the order of their reactivity.

Example: Sodium is more reactive than iron.

🔹 Occurrence of Metals

• Native State: Found in free state (e.g., gold, platinum)

• Combined State: Found as compounds (e.g., oxides, sulphides)

🔹 Extraction of Metals

1. Low Reactivity Metals: By reduction (e.g., Au, Ag)

2. Medium Reactivity Metals: Roasting and reduction (e.g., Zn, Fe)

3. High Reactivity Metals: Electrolysis (e.g., Na, Al)

🔹 Corrosion

• Gradual destruction of metals due to reaction with air, moisture, etc.

• Example: Rusting of iron

  • Fe + O₂ + H₂O → Fe₂O₃·xH₂O (rust)

Prevention: Painting, galvanizing, oiling, alloying.

🔹 Alloys

• A mixture of two or more metals (or metals and non-metals).

• Improves properties like strength, corrosion resistance.

Example: