Chapter 4: The World of Metals and Non-metals
From an ironsmith's forge to the Iron Pillar of Delhi, metals shape our lives. In this chapter we test materials for lustre, malleability, ductility, sonority and conduction, see how air and water rust iron, burn magnesium and sulfur to compare their oxides, and discover why non-metals matter just as much.
In this chapter you will
- compare the properties of metals and non-metals
- explain malleability, ductility, sonority and conduction
- find the conditions for rusting
- compare metal and non-metal oxides and list uses
Topics
- Malleability, Ductility and Sonority NCERT 4.1.1–4.1.3
Metals are lustrous, malleable (sheets), ductile (wires) and sonorous (ring).
- Conduction of Heat and Electricity NCERT 4.1.4–4.1.5
Metals conduct heat and electricity well; non-metals like sulfur and coal do not.
- Effect of Air and Water on Metals NCERT 4.2–4.3
Iron rusts only with both air and water; rusting is a kind of corrosion.
- Non-metals and Their Uses NCERT 4.4–4.5
Non-metals are dull, brittle, poor conductors and form acidic oxides.
Key words
- Lustre
- the shine of metals
- Malleable
- can be beaten into sheets
- Ductile
- can be drawn into wires
- Sonorous
- makes a ringing sound
- Brittle
- breaks into pieces when hit
- Corrosion / rusting
- slow damage of metals by air and water; rust on iron
- Element
- a substance that cannot be broken into simpler ones
Summary
- Metals: lustrous, hard (mostly), malleable, ductile, sonorous, good conductors.
- Non-metals: dull, brittle, poor conductors.
- Iron rusts in moist air; metal oxides are basic, non-metal oxides acidic.
- Non-metals like oxygen, carbon, nitrogen, chlorine and iodine are essential.