Some metals react more than others

Metals are not all equally reactive. Potassium fizzes violently in water; gold sits in a ring for centuries without changing. We can put metals in order of how readily they react — this is the reactivity series.

• A metal high up is very reactive — it reacts fast with water, acids and oxygen.
• A metal low down is unreactive — it barely reacts at all.
• Carbon (a non-metal) is placed in the list too, because its position tells us how to extract metals.

Why it matters: the order predicts what will react, how we store metals, and — most importantly for KS3 — how we get pure metals out of the ground.

The reactivity ladder

Here is the KS3 order, most reactive at the top. Notice exactly where carbon sits.

Watch out: carbon is a non-metal, but we still list it here — its rung is the dividing line for extraction, which you'll meet in a moment.

Where does carbon sit?

How we know the order

We put metals in order by watching how vigorously they react. Two easy tests are used at KS3:

• With water: potassium and sodium fizz fast (potassium even catches fire); calcium bubbles steadily; magnesium reacts only very slowly; copper, silver and gold do nothing.
• With dilute acid: magnesium bubbles fast, zinc more gently, iron slower still, and copper gives no bubbles at all.

Golden rule: the more vigorous the reaction (more bubbles, more heat, faster), the higher the metal sits in the series.

The more reactive metal pushes the other one out

A displacement reaction happens when a more reactive metal takes the place of a less reactive metal in its compound. The more reactive metal "wins" the oxygen or the other part of the compound.

Key idea: displacement only works one way — a more reactive metal displaces a less reactive one, never the other way round.

The word equation

Displacement reactions are written as word equations. The reactive metal ends up in the new compound; the less reactive metal is set free:

Will it react?

Which is more reactive?

Tap the more reactive one each time. Use the ladder.

Metals are usually found as compounds

Most metals are too reactive to be found pure in the ground. They are locked up in rocks called ores, often as metal oxides (metal joined to oxygen). To get the metal we must remove the oxygen — this is called reduction.

• Gold is so unreactive it is usually found as the metal itself — no reaction is needed to free it.
• Iron and copper are found in ores as compounds and must be extracted.
• The method we choose depends on where the metal sits relative to carbon.

Carbon steals the oxygen

If a metal is below carbon in the series, we can heat its oxide with carbon. Carbon is more reactive than the metal, so carbon grabs the oxygen and the pure metal is left behind. Iron is made from iron ore using carbon, in a blast furnace.

Rule of thumb: carbon can extract any metal below it (zinc, iron, lead, copper). Metals above carbon (potassium, sodium, calcium, magnesium, aluminium) are too reactive — carbon can't remove their oxygen, so they need a different method (electrolysis).

Can carbon do it?

Explain your reasoning

Why is gold found as metal, but iron is locked in rock?

Why a ceramic mug, a plastic bottle and a carbon-fibre bike?

Ceramics — hard, heat-proof, brittle

A ceramic is made by heating clay or sand to a very high temperature. Think pottery, bricks, china and glass.

• Hard and stiff — good for surfaces that must not scratch.
• Withstand very high temperatures — used to line furnaces and make oven dishes.
• Do not conduct electricity — used as insulators.
• Brittle — they can shatter if dropped, so no good for things that get knocked about.

Everyday use: a coffee mug (ceramic) survives boiling water without melting, but cracks if you drop it — hard but brittle.

Polymers — light, flexible, mouldable

A polymer is a substance made of very long chain molecules. Plastics are polymers. Most plastics come from crude oil.

• Light. Many are flexible (bend without breaking); some are hard and stiff.
• Easily moulded into any shape — bottles, toys, casings.
• Waterproof and good electrical insulators — used to coat wires.
• Usually soften or melt when heated, so not for very hot jobs.

Everyday use: a drinks bottle (polymer) is light, does not shatter if dropped, and is waterproof — but would sag near a flame.

Composites — best of both worlds

A composite is made by combining two or more materials to get properties that none of them has alone. It has a matrix (the material that holds it together) with a reinforcement (fibres or lumps) spread through it.

Everyday use: concrete is a composite (stone/gravel held in cement); carbon-fibre bike frames (carbon fibres in a plastic matrix: light, strong and stiff) and fibreglass boats are composites too.

Pick the right material

Don't fall for these

• "The less reactive metal displaces the more reactive one." ❌ It's the other way round — the more reactive metal always wins and displaces the less reactive one.
• "Carbon can extract any metal." ❌ Carbon can only extract metals below it (zinc, iron, lead, copper). Metals above carbon (like aluminium) need electrolysis.
• "Ceramics, polymers and composites are all the same." ❌ Ceramics are hard but brittle; polymers are light, often flexible, and soften when hot; composites combine materials to get the best of both.
• "A composite just has all the properties of its parts." ❌ The parts work together to give new properties: fibreglass does not shatter like glass, and is much stiffer than the plastic alone.

Match the material to its use

Tap a use on the left, then its best material on the right.

Lock it in

One last question before your trophy — put it all together.

Put it together