Chemistry

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Metals, ores, metallurgy and alloys

⏱ 5 min read🧩 6 question types🎯 19 practice Q

The idea in one minute

Metals shine, bend and carry electricity, and a few exceptions are popular exam picks. This lesson pairs each metal with its ore, walks through the steps of extraction, and lists the reactivity series and alloy recipes. It ends with rusting and gold purity.

Metals and non-metals

Metals are lustrous, malleable, ductile and sonorous. They conduct heat and electricity. Non-metals are mostly dull, brittle and poor conductors.

The exceptions are the exam favourites.

Mercury is a liquid metal.
Sodium and potassium are soft metals. A knife cuts them.
Graphite is a non-metal that conducts electricity.
Iodine is a lustrous non-metal.
Diamond is the hardest natural substance, and it is a non-metal.

Ore and metal

Metal	Main ore
Aluminium	Bauxite (Al₂O₃·2H₂O)
Iron	Haematite (Fe₂O₃), magnetite (Fe₃O₄), siderite
Copper	Copper pyrites (chalcopyrite), malachite, cuprite
Zinc	Zinc blende (ZnS), calamine
Lead	Galena (PbS)
Mercury	Cinnabar (HgS)
Tin	Cassiterite (SnO₂)
Uranium	Pitchblende
Silver	Argentite
Sodium	Rock salt
Magnesium	Magnesite, dolomite, carnallite
Calcium	Limestone, gypsum

Extracting a metal

Metallurgy has four steps.

Concentration. Froth flotation suits sulphide ores. Pine oil is used. Magnetic and gravity separation also work.
Convert to oxide. Calcination heats a carbonate ore in limited air. Roasting heats a sulphide ore in excess air.
Reduction. Carbon reduces iron in the blast furnace. Very reactive metals need electrolysis: aluminium (Hall-Héroult process), sodium, potassium.
Refining. In electrolytic refining the impure metal is the anode. Pure metal collects on the cathode. Copper is refined this way.

Tip: Calcination goes with carbonate. Roasting goes with sulphide.

The reactivity series

\text{K} > \text{Na} > \text{Ca} > \text{Mg} > \text{Al} > \text{Zn} > \text{Fe} > \text{Pb} > (\text{H}) > \text{Cu} > \text{Hg} > \text{Ag} > \text{Au}

Metals above hydrogen give H₂ with dilute acids. Copper, silver and gold do not.
Sodium and potassium are stored under kerosene. White phosphorus is stored under water.
Gold and platinum are noble metals. They occur free in nature.
A more reactive metal displaces a less reactive one from its salt solution. An iron nail in copper sulphate turns brown.

Rusting and corrosion

Rusting needs both air and moisture. Rust is hydrated iron oxide, Fe₂O₃·xH₂O.

Prevention: galvanisation (zinc coating), painting, greasing, electroplating, and alloying into stainless steel.
Silver tarnishes black (Ag₂S). Copper grows a green coat of basic copper carbonate.
Aluminium protects itself with a thin oxide film. Anodising makes it thicker.

Alloys

Alloy	Made of	Use
Brass	Copper + zinc	Utensils, fittings
Bronze	Copper + tin	Statues, medals
Bell metal	Copper + more tin	Bells, gongs
Gun metal	Copper + tin + zinc	Gears, castings
German silver	Copper + zinc + nickel (no silver)	Utensils
Solder	Lead + tin	Joins wires; low melting point
Stainless steel	Iron + chromium + nickel + carbon	Cutlery
Duralumin	Aluminium + copper + magnesium + manganese	Aircraft
Magnalium	Aluminium + magnesium	Light instruments
Nichrome	Nickel + chromium	Heater coils
Invar	Iron + nickel	Pendulums, tapes
Amalgam	Any metal + mercury	Dental fillings

Gold purity

24 carat is pure gold. Use $\text{Purity}\,(\%) = \dfrac{\text{carat}}{24} \times 100$ . So 18 carat is 75%, and 22 carat is about 91.67%. Jewellery gold is mixed with copper or silver to make it hard.

Question types you will see

Each type: how to recognise it, the method step by step, and one question to try.

Type 1very common3 practice Q

Ore and metal matching

How to spot it:

The question says 'bauxite is the ore of', 'cinnabar is an ore of', or gives a match-the-column of ores and metals.

Method

Learn the headline pairs: bauxite-Al, haematite-Fe, cinnabar-Hg, galena-Pb.
Add zinc blende-Zn, cassiterite-Sn, copper pyrites-Cu, pitchblende-U, rock salt-Na.
Extra ores: calamine is zinc; magnetite and siderite are iron.
In a match, fix the surest pair first and chain the rest.

Why it works:

Ore names are fixed, so recall by pairs works better than logic.

Try this

Cinnabar is an ore of which metal?

Show solution

Cinnabar is HgS.
Hg is mercury.

Answer

Mercury

Type 2very common3 practice Q

Alloy and composition

How to spot it:

The question asks 'brass is an alloy of', 'which alloy contains tin', or what is added to iron for stainless steel.

Method

Copper family: brass Cu + Zn, bronze Cu + Sn, bell metal Cu + more Sn, German silver Cu + Zn + Ni.
Iron family: stainless steel Fe + Cr + Ni, invar Fe + Ni.
Others: duralumin Al + Cu, magnalium Al + Mg, solder Pb + Sn, nichrome Ni + Cr.
Amalgam always has mercury.

Why it works:

Each alloy has a fixed recipe, and the second metal is what exams test.

Try this

Brass is an alloy of which metals?

Show solution

Brass is a copper alloy.
The partner is zinc, not tin.

Answer

Copper and zinc

Type 3common3 practice Q

Metallurgy steps and processes

How to spot it:

The question says 'roasting is used for', 'calcination vs roasting', 'froth flotation', or 'which metal is extracted by electrolysis'.

Method

Concentrate the ore. Froth flotation is for sulphide ores.
Calcination: carbonate ore, limited air. Roasting: sulphide ore, excess air.
Reduce with carbon (iron) or by electrolysis (Al, Na).
Refine copper electrolytically with the impure metal as the anode.

Why it works:

Each step prepares the ore for the next, from ore to pure metal.

Try this

Roasting is done for which type of ore?

Show solution

Roasting uses excess air.
It turns sulphides into oxides and drives off SO₂.

Answer

Sulphide ores

Type 4common3 practice Q

Reactivity series consequences

How to spot it:

The question asks which metal gives no H₂ with dilute acid, why sodium is kept in kerosene, or which metal occurs free.

Method

Write the series: K, Na, Ca, Mg, Al, Zn, Fe, Pb, H, Cu, Hg, Ag, Au.
Metals above H give H₂ with dilute acids.
Top metals burn in moist air, so keep them under kerosene.
Bottom metals occur free. A more reactive metal displaces a less reactive one.

Why it works:

Position in the series tells you how eagerly a metal reacts.

Try this

Which metal will not liberate hydrogen from dilute hydrochloric acid?

Show solution

Find hydrogen in the series.
Copper lies below it.

Answer

Copper (also silver, gold, mercury)

Type 5common2 practice Q

Corrosion and its prevention

How to spot it:

The question says 'rusting requires', 'galvanisation is coating with', 'green coating on copper', or 'anodising is done on'.

Method

Rusting needs air and moisture together.
Prevent with galvanising, paint, oil, electroplating, anodising or alloying.
Colours: iron is red-brown rust; copper is green; silver is black.

Why it works:

Each prevention method keeps air or water away from the metal.

Try this

A green coating slowly forms on a copper vessel left in damp air. What is it?

Show solution

Copper reacts slowly with moist air.
It forms basic copper carbonate.

Answer

Basic copper carbonate (silver turns black with Ag₂S)

Type 6common2 practice Q

Metal and non-metal exceptions, gold carat

How to spot it:

The question asks which metal is liquid or soft, which non-metal conducts, the most ductile metal, or a carat purity.

Method

Exceptions: Hg liquid; Na and K soft; graphite conducts; iodine lustrous.
Best metal conductor: silver. Most ductile: gold. Highest melting point: tungsten.
Purity = carat ÷ 24 × 100.

Why it works:

The exceptions break the general rule, so questions love them.

Try this

Which non-metal conducts electricity?

Show solution

Carbon layers in graphite hold free electrons.
These carry current.

Answer

Graphite

Formula sheet

Gold purity

\text{Purity}\,(\%) = \frac{\text{carat}}{24} \times 100

22 ct ≈ 91.67%

Shortcuts that save time

⚡ Reactivity series sentence

Please Stop Calling Me A Zebra, I Like Her Calling Me Smart Goat gives Potassium, Sodium, Calcium, Magnesium, Aluminium, Zinc, Iron, Lead, Hydrogen, Copper, Mercury, Silver, Gold.

⚡ Brass or bronze

Brass has zinc. Bronze has tin. Both have copper.

Example

Bronze is an alloy of which metals?

Show solution

Bronze is a copper alloy.
The partner metal is tin.

Answer

Copper and tin

Mistakes to avoid

Where most students lose marks on this subtopic.

Mistake 01

Believing German silver contains silver.

It is copper, zinc and nickel.

Mistake 02

Naming haematite as an aluminium ore.

Haematite is iron. Bauxite is aluminium.

Mistake 03

Saying solder has a high melting point.

Solder melts easily. That is why it joins wires.

Mistake 04

Mixing up calcination and roasting.

Calcination is for carbonates in limited air. Roasting is for sulphides in excess air.

Mistake 05

Saying brass is copper and tin.

Brass is copper and zinc. Bronze is copper and tin.

Quick revision

Read this the night before the exam.

Calcination: carbonate. Roasting: sulphide. Froth flotation: sulphide ores.
Bauxite: Al. Haematite: Fe. Cinnabar: Hg. Zinc blende: Zn. Galena: Pb. Cassiterite: Sn. Pitchblende: U.
K > Na > Ca > Mg > Al > Zn > Fe > Pb > H > Cu > Hg > Ag > Au.
Cu, Ag and Au give no H₂ with dilute acid.
Brass: Cu + Zn. Bronze: Cu + Sn. Solder: Pb + Sn. Duralumin: Al + Cu. Nichrome: Ni + Cr.
Rusting needs air and moisture. Galvanising is a zinc coat.
Amalgam is a metal with mercury. 24 carat is pure gold.

Practice: 19 questions

Sets of 10, mixed across the question types above. Every answer has a step-by-step explanation.

Topic test · 10 questions

Suggested time 3 min · wrong answers go to your mistake notebook automatically.

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