The Reactivity Series of Metals: KS3 Chemistry

The reactivity series is a ranked list of metals ordered from most to least reactive. It is a fundamental concept in KS3 chemistry, typically taught in Year 8 or 9, and it allows you to predict how metals will behave in chemical reactions and which metals can displace others from their compounds.

What does the reactivity series show?

The reactivity series ranks metals by how readily they react with other substances — particularly water, dilute acids and oxygen. A metal that reacts vigorously sits near the top of the series; a metal that barely reacts at all sits near the bottom.

Two non-metals — carbon and hydrogen — are included in the series as reference points, even though they are not metals. Carbon is important because it is used in industry to extract metals less reactive than itself from their ores (a form of displacement). Hydrogen is included so you can immediately see which metals will react with dilute acid to produce hydrogen gas (those above hydrogen) and which will not (those below).

The reactivity series in order (most to least reactive)

Rank | Element | Metal or non-metal?
1 | Potassium (K) | Metal
2 | Sodium (Na) | Metal
3 | Calcium (Ca) | Metal
4 | Magnesium (Mg) | Metal
5 | Aluminium (Al) | Metal
6 | Carbon (C) | Non-metal (reference)
7 | Zinc (Zn) | Metal
8 | Iron (Fe) | Metal
9 | Hydrogen (H) | Non-metal (reference)
10 | Copper (Cu) | Metal
11 | Silver (Ag) | Metal
12 | Gold (Au) | Metal
13 | Platinum (Pt) | Metal

A common mnemonic used in UK classrooms is: Please Send Cats Milk And Chicken Zoup Instead Having Chicken Sandwiches Generally Prefers.

How does reactivity differ across the series?

Reactions with cold water

Metal | Reaction with cold water
Potassium | Very vigorous — burns with a lilac flame; hydrogen gas released
Sodium | Vigorous — fizzes and moves on water surface; hydrogen released
Calcium | Moderate — steady fizzing; hydrogen released; calcium hydroxide formed
Magnesium | Very slow with cold water; reacts readily with steam
Zinc, iron | No visible reaction with cold water
Copper, silver, gold | No reaction

Reactions with dilute acid

Metal | Reaction with dilute hydrochloric acid
Magnesium | Very fast — vigorous fizzing, hydrogen gas produced
Zinc | Moderate — steady fizzing, hydrogen gas produced
Iron | Slow — gentle fizzing, hydrogen gas produced
Copper | No reaction
Silver, gold | No reaction

Hydrogen gas can be confirmed with the squeaky pop test: hold a lit splint near the gas and it ignites with a squeaky pop.

What is a displacement reaction?

A displacement reaction occurs when a more reactive metal pushes a less reactive metal out of a compound (usually a salt solution). The more reactive metal takes the place of the less reactive one — it "displaces" it.

The general rule is: a more reactive metal will displace a less reactive metal from its salt solution.

Worked example 1: iron and copper sulfate solution

Iron is above copper in the reactivity series.

Iron + copper sulfate → iron sulfate + copper

Fe + CuSO₄ → FeSO₄ + Cu

When an iron nail is placed in blue copper sulfate solution, the solution gradually turns pale green (iron sulfate) and a coating of reddish-brown copper metal forms on the nail. Iron displaces copper from the solution.

Worked example 2: copper and zinc sulfate solution

Copper is below zinc in the reactivity series.

Copper + zinc sulfate → no reaction

If copper is placed in zinc sulfate solution, nothing happens. Copper cannot displace zinc because it is less reactive.

Worked example 3: zinc and dilute acid vs copper and dilute acid

Zinc + dilute hydrochloric acid → zinc chloride + hydrogen (zinc is above hydrogen: reacts)

Copper + dilute hydrochloric acid → no reaction (copper is below hydrogen: does not react)

This is a direct, testable comparison that appears frequently in KS3 and GCSE exam questions.

How is the reactivity series used in industry?

The reactivity series determines how metals are extracted from their ores:

Carbon reduction — metals below carbon (zinc, iron) can be extracted by heating their ores with carbon (coke). Carbon displaces the metal from its oxide. This is how iron is made in a blast furnace.

Electrolysis — metals above carbon (aluminium, calcium, sodium) are too reactive to be displaced by carbon; they must be extracted using electrolysis, which requires a great deal of electrical energy. This is why aluminium is more expensive to produce than iron.

Found native (uncombined) — metals at the very bottom of the series (copper, silver, gold, platinum) are so unreactive that they occur as pure elements in nature, without being combined with other elements in compounds.

According to the Department for Education's Science Programmes of Study for Key Stage 3, pupils should learn about the order of reactivity of metals and how the reactivity series relates to displacement reactions.

BBC Bitesize KS3 Chemistry covers the reactivity series, reactions of metals with water and acid, and displacement reactions as core content for Year 8 and Year 9 chemistry (see bbc.co.uk/bitesize/subjects/zrkw2hv).

Frequently asked questions

What does the reactivity series show?

The reactivity series is a list of metals (and two non-metals, carbon and hydrogen, for reference) ranked from most to least reactive. It summarises how readily each metal reacts with substances such as water, dilute acids and oxygen. The series allows chemists and students to predict the outcome of chemical reactions: a metal higher in the series will react more vigorously than one lower down, and will be able to displace a less reactive metal from its compound.

What is a displacement reaction?

A displacement reaction is a reaction in which a more reactive element displaces (pushes out) a less reactive element from a compound. In KS3 chemistry, this usually means a more reactive metal displacing a less reactive metal from its salt solution. For example, placing iron into copper sulfate solution causes iron to displace copper, because iron is higher in the reactivity series. The copper appears as a solid deposit and the solution changes colour from blue to pale green.

Why don't gold and platinum react with acids?

Gold and platinum sit at the very bottom of the reactivity series, meaning they have very little tendency to form positive ions (to lose electrons and react). Their atoms hold onto their electrons very tightly. As a result, gold and platinum do not react with dilute acids, and they are even resistant to concentrated acids individually. They can only be dissolved in aqua regia (a mixture of concentrated nitric acid and concentrated hydrochloric acid). This extreme stability is why gold has been used for coins and jewellery for thousands of years — it does not tarnish or corrode.

How can you use the reactivity series to predict reactions?

To predict whether a reaction will occur, compare the positions of the substances in the reactivity series. If a metal is higher than another metal in a salt solution, it will displace it (reaction occurs). If a metal is higher than hydrogen, it will react with dilute acid to produce hydrogen gas (reaction occurs). If a metal is lower than hydrogen, it will not react with dilute acid (no reaction). The same logic applies to reducing metal oxides: carbon reduces metal oxides only when carbon is above the metal in the series.

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