📑 Topics on this page (Jump to Topic):
📌 1. Properties of Metals & Non-metals
| Property | Metals | Non-metals |
|---|---|---|
| Lustre | Lustrous | Usually not (exceptions: iodine, graphite, diamond) |
| Malleable & ductile | Yes — gold most; silver too | No, brittle |
| Conductivity | Good conductors — silver > copper > aluminium; lead poor | Poor (exception: graphite) |
| State | Solid (exception: mercury liquid; gallium and caesium melt in the palm) | Solid/liquid/gas (bromine liquid) |
| Oxides | Basic (Al₂O₃, ZnO amphoteric) | Acidic or neutral (CO, N₂O, H₂O) |
| Sound | Sonorous — bells | No |
- Reactivity series: K > Na > Ca > Mg > Al > Zn > Fe > Pb > [H] > Cu > Hg > Ag > Au. A higher metal displaces a lower one from its salt. Metals below H do not release H₂ from acids.
- Sodium and potassium are soft (cut with a knife) and kept in kerosene; white phosphorus is kept under water (it catches fire in air).
- Diamond is the hardest natural substance; graphite is a non-metal that conducts electricity.
📌 2. Ores & Metallurgy
| Metal | Main ore |
|---|---|
| Aluminium | Bauxite (Al₂O₃·2H₂O), cryolite |
| Iron | Haematite (Fe₂O₃), magnetite (Fe₃O₄ — richest), siderite |
| Copper | Copper pyrites (CuFeS₂), malachite |
| Zinc | Zinc blende (ZnS), calamine (ZnCO₃) |
| Lead | Galena (PbS) |
| Mercury | Cinnabar (HgS) |
| Tin | Cassiterite (SnO₂) |
| Sodium | Rock salt (NaCl) |
| Uranium | Pitchblende |
- A mineral is a natural compound; an ore is one from which metal can be extracted profitably. All ores are minerals, not all minerals are ores.
- Roasting — heating sulphide ores in air; calcination — heating carbonate ores without air; froth flotation — concentrating sulphide ores.
- Highly reactive metals (Na, K, Ca, Mg, Al) are extracted by electrolysis; iron by reduction with coke in a blast furnace. Cast iron (2–4.5% C), wrought iron (purest), steel (0.1–1.5% C).
📌 3. Alloys
| Alloy | Components | Uses |
|---|---|---|
| Brass | Copper + zinc | Utensils, taps |
| Bronze | Copper + tin | Statues, medals, bells |
| Stainless steel | Iron + chromium + nickel (+ C) | Utensils, surgical tools — rust-proof |
| Solder | Lead + tin | Joining electric wires (low m.p.) |
| Nichrome | Nickel + chromium | Heater and iron elements |
| Duralumin | Aluminium + copper + Mg + Mn | Aircraft bodies (light, strong) |
| German silver | Copper + zinc + nickel (no silver!) | Utensils, coins |
| Amalgam | Mercury + any other metal | Dental fillings (silver amalgam) |
- Pure gold is 24 carat; 22 carat = 22 parts gold + 2 parts copper/silver (for strength).
⚠️ Exam Traps:
- German silver contains no silver.
- Brass = Cu + Zn; bronze = Cu + Sn — do not swap.
- Bauxite is an ore of aluminium, not iron.
📌 4. Practice MCQs
📝 Practice MCQs (prepared by SF Prep — not PYQs)
Q1. Brass is an alloy of: Practice
Correct answer: (C)
Bronze = copper + tin.
Bronze = copper + tin.
Q2. The main ore of aluminium is: Practice
Correct answer: (A)
Al₂O₃·2H₂O; Al is extracted by electrolysis.
Al₂O₃·2H₂O; Al is extracted by electrolysis.
Q3. The metal that is liquid at room temperature is: Practice
Correct answer: (A)
Bromine is liquid but a non-metal.
Bromine is liquid but a non-metal.
Q4. The most malleable metal is: Practice
Correct answer: (B)
Gold can be beaten into extremely thin leaves.
Gold can be beaten into extremely thin leaves.
Q5. The best conductor of electricity is: Practice
Correct answer: (B)
Copper is used in wires because silver is costly.
Copper is used in wires because silver is costly.
Q6. White phosphorus is stored in: Practice
Correct answer: (D)
It catches fire spontaneously in air.
It catches fire spontaneously in air.
Q7. Galena is an ore of: Practice
Correct answer: (A)
PbS.
PbS.
Q8. Stainless steel contains iron mainly with: Practice
Correct answer: (D)
A chromium oxide layer prevents rusting.
A chromium oxide layer prevents rusting.
Q9. Solder is made of: Practice
Correct answer: (D)
Its low melting point makes it useful for joining.
Its low melting point makes it useful for joining.
Q10. Which metal is NOT present in German silver? Practice
Correct answer: (B)
Cu + Zn + Ni; named only for its silvery look.
Cu + Zn + Ni; named only for its silvery look.
Q11. The richest ore of iron is: Practice
Correct answer: (C)
Fe₃O₄ has about 72% iron.
Fe₃O₄ has about 72% iron.
Q12. Cinnabar is an ore of: Practice
Correct answer: (C)
HgS.
HgS.
Q13. The light alloy used for aircraft bodies is: Practice
Correct answer: (D)
Aluminium-based — light and strong.
Aluminium-based — light and strong.
Q14. An amalgam always contains: Practice
Correct answer: (A)
Mercury + another metal.
Mercury + another metal.
Q15. The fraction of pure gold in 22-carat gold is: Practice
Correct answer: (D)
≈ 91.7%; the rest is copper/silver.
≈ 91.7%; the rest is copper/silver.
Q16. A non-metal that is a good conductor of electricity is: Practice
Correct answer: (C)
Graphite has free electrons.
Graphite has free electrons.
Q17. Among the most reactive metals in the reactivity series is: Practice
Correct answer: (B)
K > Na > Ca ...; gold is at the bottom.
K > Na > Ca ...; gold is at the bottom.
Q18. Why does copper not release hydrogen from dilute HCl? Practice
Correct answer: (A)
Metals less reactive than H cannot displace H⁺ from acids.
Metals less reactive than H cannot displace H⁺ from acids.
Q19. Heating a sulphide ore in the presence of air is called: Practice
Correct answer: (C)
Calcination is for carbonate ores without air.
Calcination is for carbonate ores without air.
Q20. The metal that melts on keeping in the palm is: Practice
Correct answer: (B)
Gallium melts at about 29.8 °C.
Gallium melts at about 29.8 °C.