Chemistry 0620 · syllabus 9
Cambridge IGCSE Chemistry 0620 — Metals topical past papers
Properties and uses of metals and alloys, the reactivity series and displacement, rusting and how to prevent it, and the extraction of iron and aluminium.
- Questions
- 982
- Years
- 2009–2026
- With mark scheme
- 98%
- Questions 2022–2026
- 337
Anyone can browse these pages. Opening the questions and their mark schemes takes a free Momentum account.
What Metals covers
Metals conduct heat and electricity, are malleable and ductile, and usually have high melting and boiling points; non-metals are generally the opposite. Their properties explain their uses: aluminium in aircraft for its low density, in overhead cables for its low density and good conductivity, and in food containers because it resists corrosion; copper in wiring because it conducts well and is ductile. An alloy is a mixture of a metal with other elements, such as brass (copper and zinc) or stainless steel (iron with chromium, nickel and carbon), and it can be harder and stronger than the pure metal; on the Extended route you explain why: atoms of different sizes disrupt the layers, so they can no longer slide over each other.
The reactivity series, potassium, sodium, calcium, magnesium, aluminium, carbon, zinc, iron, hydrogen, copper, silver, gold, ranks metals by how readily they react. Potassium, sodium and calcium react with cold water and magnesium with steam; metals above hydrogen give hydrogen with dilute hydrochloric acid, while copper, silver and gold do not. You deduce an order from experimental results, and on the Extended route you explain it as a metal's tendency to form positive ions, seen in displacement: a metal displaces a less reactive metal's ions from solution. Aluminium seems less reactive than its position suggests because a thin oxide layer protects it.
Iron and steel rust when both water and oxygen are present, forming hydrated iron(III) oxide. Paint, grease and plastic coatings stop rusting by keeping water and oxygen out, and so does galvanising with zinc, which on the Extended route you also explain as sacrificial protection: zinc is more reactive, so it loses electrons instead of the iron. How a metal is extracted depends on its reactivity. In the blast furnace, coke burns to give heat and carbon dioxide, the carbon dioxide is reduced to carbon monoxide, the carbon monoxide reduces iron(III) oxide in hematite to iron, and limestone decomposes to calcium oxide, which removes impurities as slag. Aluminium is too reactive to be reduced by carbon, so it is extracted from bauxite by electrolysis; Extended candidates write the equations for both processes and explain the roles of cryolite and the carbon anodes.
In the syllabus
The headings this topic has in the Cambridge International 2026–2028 syllabus, as the board prints them.
- 9 Metals
- 9.1 Properties of metals
- 9.2 Uses of metals
- 9.3 Alloys and their properties
- 9.4 Reactivity series
- 9.5 Corrosion of metals
- 9.6 Extraction of metals
What you should be able to do
- Compare the physical properties of metals and non-metals, and link the uses of aluminium, copper and alloys to their properties
- Identify alloys from diagrams of their structure, and on the Extended route explain why alloys are harder than pure metals
- Recall the reactivity series and describe the reactions of metals with cold water, steam and dilute hydrochloric acid
- Deduce an order of reactivity from experimental results, including displacement reactions on the Extended route
- State the conditions for rusting and describe barrier methods, and on the Extended route explain galvanising as sacrificial protection
- Describe the extraction of iron in the blast furnace and of aluminium by electrolysis, with equations on the Extended route
Key ideas
- Reactivity series: K, Na, Ca, Mg, Al, C, Zn, Fe, H, Cu, Ag, Au
- A metal displaces a less reactive metal from its compounds: Zn(s) + CuSO₄(aq) → ZnSO₄(aq) + Cu(s)
- Rusting needs water and oxygen; rust is hydrated iron(III) oxide
- Blast furnace: C + O₂ → CO₂; C + CO₂ → 2CO; Fe₂O₃ + 3CO → 2Fe + 3CO₂; CaCO₃ → CaO + CO₂; CaO + SiO₂ → CaSiO₃ (slag)
- Aluminium: Al₂O₃ dissolved in molten cryolite; cathode Al³⁺ + 3e⁻ → Al; anode 2O²⁻ → O₂ + 4e⁻, and the oxygen burns the carbon anodes away
How Metals has been examined
From 2022 to 2026, Metals was on Paper 4 · Theory (Extended) in 14 of 14 exam series, worth about 21% of that paper’s marks.
| Paper | Questions | Share of marks | Series |
|---|---|---|---|
| Paper 1 · Multiple Choice (Core) | 121 | 9% | 14 of 14 |
| Paper 2 · Multiple Choice (Extended) | 128 | 10% | 14 of 14 |
| Paper 3 · Theory (Core) | 42 | 18% | 14 of 14 |
| Paper 4 · Theory (Extended) | 40 | 21% | 14 of 14 |
| Paper 6 · Alternative to Practical | 6 | 4% | 4 of 14 |
Momentum’s own count, over the questions in its bank for these years: a series is one exam session, every zone included, and a question filed under two chapters counts in both. Median marks per question: 1.
Filed in Momentum under: The Behavior of Metals, Making Use of Metals.
A worked example
A blast furnace is loaded with 2.00 tonnes of hematite containing 80.0% iron(III) oxide by mass. Fe₂O₃(s) + 3CO(g) → 2Fe(l) + 3CO₂(g). Calculate the maximum mass of iron that can be produced and the mass of carbon monoxide needed to reduce all the iron(III) oxide.
- Mass of Fe₂O₃ = 0.800 × 2.00 = 1.60 tonnes = 1.60 × 10⁶ g
- Mr of Fe₂O₃ = (2 × 56) + (3 × 16) = 160, so moles of Fe₂O₃ = 1.60 × 10⁶ ÷ 160 = 1.00 × 10⁴ mol
- Each mole of Fe₂O₃ gives 2 mol of iron: 2.00 × 10⁴ mol × 56 = 1.12 × 10⁶ g = 1.12 tonnes
- Each mole of Fe₂O₃ needs 3 mol of CO: 3.00 × 10⁴ mol × 28 = 8.40 × 10⁵ g = 0.840 tonnes
- Check by mass: iron is 112/160 = 70.0% of Fe₂O₃, and 70.0% of 1.60 tonnes is 1.12 tonnes
Answer: 1.12 tonnes of iron, using 0.840 tonnes of carbon monoxide
Written by Momentum for this page, with its own numbers; it is not taken from a past paper.
Mistakes that cost marks
- Calling aluminium unreactive because it does not corrode — it is high in the reactivity series; its thin oxide layer is what stops further reaction
- Explaining sacrificial protection as zinc being less reactive than iron — zinc is more reactive, so it is oxidised, losing electrons, instead of the iron
- Saying limestone reacts directly with the impurities — it first decomposes to calcium oxide, and the calcium oxide reacts with silicon(IV) oxide to form slag
- Calling cryolite a catalyst — aluminium oxide is dissolved in it to lower the operating temperature, which saves energy, and to improve conductivity
- Calling an alloy a compound — the elements in an alloy are mixed, not chemically combined, and their proportions can vary
Exam technique
- When ordering metals from displacement results, remember that a metal that displaces another is the more reactive, and build the order one comparison at a time
- Link the extraction method to the reactivity series: metals below carbon can be reduced with carbon or carbon monoxide; metals above it need electrolysis
- In rusting experiments, say which condition each tube removes: boiled water under a layer of oil keeps out oxygen, and a drying agent removes water
- In the blast furnace, name carbon monoxide as the reducing agent and iron(III) oxide as the substance reduced
Practising in Momentum
- Every question in a chapter as one list, from every paper and year in the bank, newest first or shuffled.
- Each question turns over to its own part of the mark scheme, where the board published one.
- Narrow by paper, year, session, zone and marks, and star the questions worth keeping.
- Pick chapters, a number of questions and a time, and the exam builder draws a mock to sit and mark.
Past-paper questions and mark schemes are the copyright of Cambridge International. Momentum shows them to signed-in learners for revision and does not publish them on these pages.