How do metals react with oxygen, water and acids, and what are displacement reactions?
Reactions of metals: reactions with oxygen, water and dilute acids, using these to place metals in a reactivity series, displacement reactions, and recycling and life cycle considerations.
A focused answer to Edexcel GCSE Chemistry topic 4, covering how metals react with oxygen, water and dilute acids, using the observations to order metals in a reactivity series, displacement reactions of more reactive metals, writing ionic equations for displacement, and why metals are recycled.
Reviewed by: AI editorial process; not yet individually human-reviewed
Have a quick question? Jump to the Q&A page
Jump to a section
What this dot point is asking
Edexcel wants you to describe how metals react with oxygen, water and dilute acids, use those observations to place metals in a reactivity series, explain and write equations for displacement reactions, and discuss recycling. The reactivity series and displacement are tested with experimental evidence and ionic equations.
Reactions with oxygen
Most metals react with oxygen to form a metal oxide:
Reactive metals such as magnesium burn brightly; less reactive metals such as iron react slowly (rusting), and gold does not react at all. The vigour of the reaction reflects reactivity.
Reactions with water and steam
Reactive metals react with water; less reactive ones react only with steam or not at all:
- The most reactive metals (potassium, sodium, lithium, calcium) react with cold water to give a metal hydroxide and hydrogen, for example .
- Metals such as magnesium and zinc react only slowly with cold water but react with steam to give the oxide and hydrogen.
- Copper, silver and gold do not react with water or steam.
Reactions with dilute acids
Metals above hydrogen in the series react with dilute acids to give a salt and hydrogen, and the rate of fizzing shows the reactivity:
The more reactive the metal, the more vigorous the fizzing. Copper, silver and gold (below hydrogen) do not react.
Building a reactivity series
By comparing how vigorously different metals react with water and acid, and which metals displace others, you can place them in order. Faster, more vigorous reactions mean a more reactive metal.
Displacement reactions
For example, iron displaces copper from copper sulfate: , with the copper appearing as a coating and the blue solution fading. The ionic equation shows the electron transfer, with sulfate as a spectator ion. A less reactive metal cannot displace a more reactive one, so the reaction tells you the order of reactivity.
Recycling metals
Recycling metal rather than extracting new metal from ore:
- conserves the finite ore and the limited reserves of metal,
- uses much less energy (especially for aluminium, where electrolysis is very energy-intensive),
- reduces waste sent to landfill and the environmental damage of mining.
Try this
Q1. Write the word equation for a metal reacting with oxygen. [1 mark]
- Cue. Metal plus oxygen gives metal oxide.
Q2. Will zinc displace magnesium from magnesium chloride solution? Explain. [2 marks]
- Cue. No, because zinc is less reactive than magnesium, so it cannot displace it.
Q3. Give two reasons why metals are recycled rather than extracted from ore. [2 marks]
- Cue. It conserves finite ore and uses much less energy (and reduces waste and mining damage).
Exam-style practice questions
Practice questions written in the style of Pearson Edexcel exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
Edexcel 20184 marksThree metals, X, Y and Z, are added separately to dilute hydrochloric acid. X fizzes vigorously, Y fizzes slowly and Z does not react. When Z is added to a solution of a salt of Y, no reaction occurs. Place X, Y and Z in order of reactivity, most reactive first, and justify your order.Show worked answer →
A 4-mark reactivity-ordering question.
The rate of fizzing with acid shows reactivity: X fizzes vigorously so it is the most reactive, Y fizzes slowly so it is in the middle, and Z does not react so it is the least reactive (1 mark for X most reactive, 1 mark for Z least reactive, 1 mark for Y in the middle). The displacement result confirms this: Z does not displace Y from its salt, so Z is less reactive than Y (1 mark). The order most reactive first is X, Y, Z.
Markers reward using both the acid reaction and the displacement result as evidence.
Edexcel 20213 marksZinc displaces copper from copper sulfate solution: . Explain why this is a displacement reaction and write the ionic equation, showing the electron transfer.Show worked answer →
A 3-mark displacement and ionic-equation question.
Zinc is more reactive than copper, so it takes the place of copper in the compound, displacing it (1 mark). The ionic equation is , with the sulfate ions as spectators (1 mark). Zinc atoms lose two electrons (oxidation) and copper ions gain two electrons (reduction) (1 mark).
Markers reward the more-reactive-metal explanation and the correctly written ionic equation with electron transfer.
Related dot points
- Extracting metals: the reactivity series, oxidation and reduction in terms of oxygen and electrons, extraction by reduction with carbon, extraction by electrolysis, and alternative biological methods.
A focused answer to Edexcel GCSE Chemistry topic 4, covering the reactivity series, oxidation and reduction defined by oxygen and by electron transfer, why a metal's position decides its extraction method, reduction with carbon for less reactive metals, electrolysis for reactive metals, and biological extraction methods.
- Reversible reactions and equilibria: reversible reactions and the use of the reversible arrow, the energy change in each direction, dynamic equilibrium in a closed system, and the idea that the conditions affect the position of equilibrium.
A focused answer to Edexcel GCSE Chemistry topic 4, covering reversible reactions and the reversible arrow, why the forward and backward reactions have opposite energy changes, what dynamic equilibrium means in a closed system, and the qualitative effect of changing conditions on the position of equilibrium.
- Reactions of acids: the general reactions of acids with metals, metal oxides, metal hydroxides and metal carbonates, the salts produced, and the tests for hydrogen and carbon dioxide.
A focused answer to Edexcel GCSE Chemistry topic 3, covering the general reactions of acids with metals, metal oxides, metal hydroxides and metal carbonates, the salts each acid produces, writing balanced and ionic equations, and the chemical tests for hydrogen and carbon dioxide.
- Transition metals, alloys and corrosion: the properties of transition metals compared with Group 1, the structure and uses of alloys, the conditions needed for rusting, and methods of preventing corrosion.
A focused answer to Edexcel GCSE Chemistry topic 5 (separate chemistry), covering the typical properties of transition metals compared with Group 1 metals, why alloys are harder than pure metals, common alloys and their uses, the conditions required for iron to rust, and methods of preventing corrosion including barriers and sacrificial protection.
- Polymers and materials: addition polymerisation of alkenes, condensation polymerisation, the properties and uses of polymers, comparing materials, and life cycle assessment.
A focused answer to Edexcel GCSE Chemistry topic 9 (separate chemistry), covering addition polymerisation of alkenes and drawing repeating units, condensation polymerisation, the properties and uses of common polymers, comparing materials such as polymers, ceramics, composites and metals, and life cycle assessment.
Sources & how we know this
- Pearson Edexcel GCSE (9-1) Chemistry (1CH0) specification — Pearson Edexcel (2016)