Science · Class 8
Materials: Metals and Non-metals
Physical and chemical properties of metals and non-metals.
4 sections15–25 min read6 MCQs · 2 examples
Chapter Overview
Metals are lustrous, malleable, ductile, conduct heat and electricity. Non-metals are dull, brittle, insulators. Both form oxides; metals react with acids producing hydrogen.
Physical Properties
- Metals: sonorous, high melting point (except mercury liquid)
- Non-metals: poor conductors (except graphite)
- Sodium stored in kerosene; phosphorus in water
Chemical Properties
- Metal + oxygen → basic oxide (MgO, Na₂O)
- Non-metal + oxygen → acidic oxide (SO₂, CO₂)
- Metal + acid → salt + H₂ gas
- Non-metals form covalent compounds
Uses and Alloys
- Aluminium: aircraft, foil; copper: wires; iron: construction
- Stainless steel: Fe + Cr + Ni; brass: Cu + Zn
Solved Examples
Step-by-step solutions — read each step before checking the final answer.
Metal test
How do you test hydrogen gas?
- 1Bring burning splint near gas
- 2Pop sound heard
- 3H₂ burns with pop
Answer
Burning splint gives pop sound
Rusting
Why is aluminium used for food wrap though reactive?
- 1Forms tough oxide layer Al₂O₃
- 2Layer prevents further reaction
- 3Light and non-toxic
Answer
Protective oxide coating
Key Points to Remember
- ✓ Iodine sublimes — non-metal exception
- ✓ Diamond (carbon) hardest natural substance
- ✓ Mercury only liquid metal at room temp
Exam Tips
- • Compare metals and non-metals in table
- • Write reaction of zinc with dilute HCl
- • Why are alloys harder than pure metals?
Practice MCQs — Materials: Metals and Non-metals
Test your understanding with topic-wise multiple choice questions. Explanations appear after each answer.
Question 1 of 6Score: 0/0
Metals are generally: