Example 1: predicting displacement
Will zinc react with lead nitrate solution?
- Zinc is above lead in the series.
- Yes: zinc + lead nitrate → zinc nitrate + lead.
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IB DemystifiedMYP Sciences
Metals and the reactivity series
Gold can lie in the ground for millions of years and still shine, while potassium bursts into flames in water. Placing metals in order of reactivity lets chemists predict their reactions, choose how to extract them from their ores, and protect steel from rusting.
Recommended for MYP 3 · About 3 lessons · Criteria A, B, C and D
On this page
- Learning objectives
- Before you start
- Key vocabulary
- Understanding the ideas
- Using the series
- Metals in the real world
- Worked examples
- Assessment tips
- Check your understanding
- Practice questions
- Investigation
- Criterion-linked questions
- Challenge questions
- Topic check
- Review your mistakes
- Your progress
Learning objectives
By the end of this topic you should be able to:
- use the reactivity series to predict reactions with water, acids and oxygen
- predict and explain displacement reactions
- link the extraction method to a metal's reactivity
- explain rusting, sacrificial protection and alloys
- analyse reactivity data and design fair experiments
- discuss mining and protecting steel
Before you start
You will use these skills. If any feel shaky, review them first.
- word and symbol equations (see Word and symbol equations; conservation of mass)
- groups and trends (see Groups and trends in the periodic table)
- acids (see Acids, alkalis and indicators)
Key vocabulary
- Reactivity series
- A list of metals in order of how readily they react.
- Displacement
- A reaction in which a more reactive metal takes the place of a less reactive one in a compound.
- Ore
- A rock containing enough of a metal compound to be worth extracting.
- Reduction
- Removing oxygen from a compound, for example by heating a metal oxide with carbon.
- Sacrificial protection
- Protecting iron by attaching a more reactive metal that corrodes instead.
- Alloy
- A mixture of a metal with other elements, such as steel or brass.
Understanding the ideas
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The reactivity series
Metals can be placed in a reactivity series. Very reactive metals such as potassium and sodium react violently with water; metals above hydrogen react with dilute acids to give hydrogen; unreactive metals such as copper, silver and gold do not react with acids.
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Displacement
A more reactive metal will displace a less reactive metal from its compounds. For example, iron in copper sulfate becomes coated with copper, and the blue colour fades.
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Extracting metals
Most metals are found as compounds in ores. Metals below carbon, such as iron and zinc, can be extracted by heating their oxides with carbon; metals above carbon, such as aluminium, need electrolysis; gold is found as the pure metal.
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Corrosion and protection
Iron rusts when exposed to air and water. It can be protected by painting, oiling, galvanising with zinc, or attaching blocks of a more reactive metal that corrodes instead. Alloys such as steel are stronger or more corrosion-resistant than pure metals.
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What does it connect to?
This topic links to equations, electrolysis, energy changes and the environmental impacts of mining.
Using the series
- With water: K, Na, Ca react with cold water; Mg reacts slowly.
- With acids: metals above hydrogen give salt + hydrogen.
- Displacement: a metal displaces any metal below it from a compound.
- Extraction: above carbon → electrolysis; below carbon → heat with carbon; gold → found pure.
- Protection: a more reactive metal (zinc, magnesium) corrodes instead of iron.
Metals in the real world
Pakistan has large copper and gold deposits at Reko Diq and Saindak in Balochistan. Galvanised steel is used for roofs and water tanks. Ships and pipelines are protected with zinc or magnesium blocks.
Worked examples
Example 2: choosing an extraction method
How would you extract zinc from zinc oxide?
- Zinc is below carbon.
- Heat zinc oxide with carbon: zinc oxide + carbon → zinc + carbon dioxide.
Assessment tips
Questions on this topic often use the reactivity series, displacement results and extraction. Expect to:
- Predict reactions from positions in the series.
- Write word and symbol equations for displacement and extraction.
- Explain extraction methods and corrosion protection.
- Analyse data to rank metals.
Common mistakes: thinking a less reactive metal can displace a more reactive one; saying all metals react with acids; confusing electrolysis with reduction by carbon; and thinking zinc protects iron only as a barrier.
Check your understanding
Quick questions on the ideas above. Try each one before using a hint.
Practice questions
Investigation: sacrificial protection
Partially guided investigation · set up 20 minutes, observe after 3–5 days · pairs
- Research question
- Which metal wrapped around an iron nail best stops it rusting in salt water?
- Scientific background
- A more reactive metal in contact with iron corrodes instead of the iron. A less reactive metal can make iron rust faster.
- Hypothesis
- Write your own prediction, with a scientific justification.
- Variables
- Identify your independent, dependent and control variables, and explain how you will control them.
- Apparatus
- Four clean iron nails, strips of magnesium ribbon, zinc and copper, four test tubes, salt water, sandpaper.
- Method
- Clean the nails with sandpaper.
- Wrap one nail tightly with magnesium, one with zinc and one with copper; leave the fourth unwrapped as a control.
- Place each nail in a test tube of salt water.
- After 3–5 days, compare how much rust has formed on each nail.
Safety. Wear eye protection when using sandpaper. Wash hands after handling metals. Dispose of solutions as instructed.
Then evaluate: explain your results using the reactivity series, and suggest why copper might make rusting worse.
Criterion-linked questions
Criterion B: inquiring and designing
Criterion C: processing and evaluating
Criterion D: reflecting on the impacts of science
Challenge questions
Harder problems in unfamiliar contexts. Plan before you calculate.
Topic check
Five questions picked at random from the whole topic. Take a new set whenever you like.
Review your mistakes
Questions you got wrong on this device appear here so you can try them again. Answer one correctly and it leaves the list.
Your progress
Tracked separately for each skill, on this device only.
| Skill | Correct | Status |
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