What you'll learn
The reactivity series ranks metals by how readily they react, and it explains how metals are extracted from their ores. In this guide you will learn the order of the reactivity series, how metals react with water and acids, how displacement reactions work, how the position of a metal decides its method of extraction, and how oxidation and reduction apply to these reactions. These ideas connect to electrolysis and to the economic importance of metals.
Key terms and definitions
Reactivity series — a list of metals in order of their reactivity, most reactive at the top.
Ore — a rock containing enough metal (or metal compound) to make extraction worthwhile.
Displacement reaction — a more reactive metal taking the place of a less reactive metal in a compound.
Oxidation — the gain of oxygen (or loss of electrons).
Reduction — the loss of oxygen (or gain of electrons).
Reduction with carbon — extracting a metal by heating its oxide with carbon.
Core concepts
The reactivity series
A common order, most to least reactive, is: potassium, sodium, lithium, calcium, magnesium, aluminium, (carbon), zinc, iron, (hydrogen), copper, silver, gold. Carbon and hydrogen (non-metals) are included as reference points because they help decide extraction methods and reactions with acids. The higher a metal is, the more readily it loses electrons to form positive ions.
Reactions with water and acids
More reactive metals react more vigorously. Potassium, sodium and lithium react with cold water to give a metal hydroxide and hydrogen. Less reactive metals like magnesium, zinc and iron react slowly or not at all with water but do react with acids to give a salt and hydrogen — the more reactive the metal, the faster the reaction. Copper, silver and gold are unreactive and do not react with dilute acids.
Displacement reactions
A more reactive metal will displace a less reactive metal from its compound (in solution). For example, iron added to copper sulfate solution displaces copper: iron + copper sulfate → iron sulfate + copper. The iron is oxidised (loses electrons) and the copper ions are reduced (gain electrons), so this is a redox reaction. Displacement reactions can be used to confirm the order of reactivity.
Oxidation and reduction
Oxidation is gain of oxygen or loss of electrons; reduction is loss of oxygen or gain of electrons (OIL RIG). When a metal reacts it is usually oxidised, forming positive ions. When a metal oxide is extracted to the metal, it is reduced.
Methods of extraction
How a metal is extracted depends on its reactivity:
- Metals less reactive than carbon (zinc, iron, copper) can be extracted by reduction with carbon, because carbon removes the oxygen.
- Metals more reactive than carbon (aluminium and above) must be extracted by electrolysis, because carbon cannot displace them.
- Very unreactive metals such as gold are found native (as the element itself) and need no extraction.
Why iron is reduced by carbon
In the blast furnace, iron oxide is heated with carbon: the carbon (or carbon monoxide) removes the oxygen from the iron oxide. The iron oxide is reduced, and the carbon is oxidised — a redox reaction.
Worked examples
Example 1: Predicting a displacement reaction
Will magnesium displace copper from copper sulfate solution?
Yes. Magnesium is more reactive than copper, so it displaces it: magnesium + copper sulfate → magnesium sulfate + copper.
Example 2: Choosing an extraction method
Why is aluminium extracted by electrolysis but iron by reduction with carbon?
Aluminium is more reactive than carbon, so carbon cannot remove its oxygen — electrolysis is needed. Iron is less reactive than carbon, so carbon can reduce iron oxide to iron.
Example 3: Identifying oxidation
In 2Mg + O₂ → 2MgO, what happens to the magnesium?
The magnesium gains oxygen, so it is oxidised (it also loses electrons to form Mg²⁺).
Common mistakes and how to avoid them
Forgetting where carbon and hydrogen sit. Their positions decide extraction methods and acid reactions.
Reversing displacement. Only a more reactive metal displaces a less reactive one.
Confusing oxidation and reduction. OIL RIG: Oxidation Is Loss, Reduction Is Gain (of electrons); also gain/loss of oxygen.
Saying all metals can be extracted with carbon. Metals above carbon (e.g. aluminium) need electrolysis.
Missing that displacement is redox. Electrons transfer from the more reactive to the less reactive metal's ions.
Exam technique for Reactivity and Extraction
Learn the reactivity series including carbon and hydrogen.
Predict reactions with water and acid based on position.
Use displacement to compare reactivity and identify redox changes.
Justify extraction methods by comparing the metal's reactivity with carbon.
Apply oxidation/reduction in terms of oxygen and electrons.
Quick revision summary
The reactivity series lists metals most-to-least reactive: potassium, sodium, lithium, calcium, magnesium, aluminium, (carbon), zinc, iron, (hydrogen), copper, silver, gold. The higher a metal, the more readily it loses electrons and reacts — the most reactive react with cold water, others only with acid, and copper, silver and gold barely react. A more reactive metal displaces a less reactive one from its compound (e.g. iron + copper sulfate → iron sulfate + copper), a redox reaction in which electrons transfer. Oxidation is gain of oxygen / loss of electrons; reduction is loss of oxygen / gain of electrons (OIL RIG). Extraction depends on reactivity: metals below carbon (zinc, iron, copper) are extracted by reduction with carbon, while metals above carbon (aluminium and up) need electrolysis, and very unreactive metals like gold occur native. Learn the series, predict reactions and displacements, justify extraction methods by comparing with carbon, and apply oxidation and reduction in both the oxygen and electron senses.