Metallic lustre
The shine has a name.
Copper, aluminium and iron shine. Coal, sulfur and wood look dull. The shine seen on a metal surface is called metallic lustre, and it is the quickest test there is.
📚 Chapter Learning Kit
The World of Metals and Non-metals · Class 7 Science · Curiosity
English 5 topics 175 leveled MCQs 85 flashcards 5 games Free
Shared by a Veda teacher · Generated with Veda AI · Oct 2026
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Malleability
Flat, not shattered.
Being hammered out into thin sheet is what malleability means. Most metals have it. Silver foil on a sweet and the foil round your lunch are both made that way.
Gold and silver
The two champions.
No metal hammers thinner than gold, with silver just behind it of all. A small amount beats out into a surprisingly large thin sheet, which is why sweet foil is silver.
Ductility
Drawn out into wires.
Where a material can be pulled out into wire, that is ductility. Metals can be. You have never seen a wire of coal or sulfur, and that is why.
Gold is the champion
One gram, two kilometres.
One gram of gold will stretch into two kilometres of wire, which is ductility at its limit. A gram is about one small paperclip.
Where metal wire goes
Three jobs for one shape.
📖 Smart notes
What you'll study, topic by topic
1
Lustre, Hardness and Malleability
Metals shine with a metallic lustre, are usually hard, and can be beaten into sheets. Coal and sulfur shatter instead, so they are brittle. A few metals break the pattern.
- The shine seen on a metal surface is called metallic lustre.
- Copper, aluminium and iron are lustrous and hard, and all three are metals.
- Coal, sulfur and wood look dull and give way more easily than any metal.
~35 min · full explanation, examples & memory tricks in the app
2
Ductility, Sonority and Conduction
Metals can be drawn into wires, ring when struck, and carry heat and electricity well. Those three properties explain wiring, bells, cooking pans and an electrician gloves.
- Ductility is the name for being able to pull a material out into wire.
- Ductility is mainly possessed by metals, and coal and sulfur are not ductile.
- Gold is so ductile that a single gram of it pulls out into two kilometres of wire.
~40 min · full explanation, examples & memory tricks in the app
3
Rusting and Corrosion
Iron rusts only where water and air meet it together. That brown deposit is rust, the process is rusting, and the wider damage to metal surfaces is corrosion.
- Iron nails kept in dry air alone show no brown deposit.
- Iron nails kept in water alone, with air excluded, also show no brown deposit.
- Only the nail exposed to both water and air develops brown deposits.
~40 min · full explanation, examples & memory tricks in the app
4
Burning in Air, and What the Oxides Do
Magnesium burns to a white powder whose solution turns red litmus blue, so metal oxides are basic. Sulfur burns to a gas that makes an acid, so non-metal oxides are acidic.
- A magnesium ribbon burns with a fierce white light and leaves a white powder.
- That white powder is magnesium oxide, made when magnesium joins with oxygen out of the air.
- A solution of magnesium oxide turns red litmus paper blue, so it is basic.
~45 min · full explanation, examples & memory tricks in the app
5
Why Non-metals Matter
Metals get noticed for shine and strength, but oxygen, carbon, nitrogen, chlorine and iodine keep us alive, fed and well. Alloys mix the two groups, and recycling metal saves waste.
- Metals are noticed for their lustre, their conductivity and their high strength.
- That does not mean non-metals are unimportant, and five of them are essential daily.
- We breathe in oxygen, a non-metal, and nobody lasts long once it is gone.
~35 min · full explanation, examples & memory tricks in the app
❓ Leveled MCQ practice
Try the smart MCQs from this kit
175 questions laddered from warm-up to topper-level, each with an explanation. A taste:
The shine shown by the surface of a metal is called
Beginner
A malleability which is a property of all metals
B brittleness
C metallic lustre
D sonority
Show answer & explanation
metallic lustre
That particular shine is named metallic lustre.
Which set contains only metals?
Beginner
A Copper, aluminium, iron
B Coal, sulfur, wood which are all dull in appearance
C Sulfur, copper, coal
D Wood, iron, coal
Show answer & explanation
Copper, aluminium, iron
Copper, aluminium and iron are all lustrous and hard, and all three are metals.
A material that can be beaten into thin sheets is said to be
Beginner
A brittle
B sonorous
C lustrous, which only describes how it looks
D malleable
Show answer & explanation
malleable
Malleability is the property of being beaten into thin sheets.
Which two metals are the most malleable of all?
Intermediate
A Iron and copper
B Gold and silver
C Sodium and potassium which are both very soft metals
D Mercury and aluminium
Show answer & explanation
Gold and silver
Gold and silver are named as the most malleable metals.
🃏 Flashcards
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