The reactivity series

What you need to know

• The reactivity series order (most to least reactive): potassium, sodium, lithium, calcium, magnesium, carbon, zinc, iron, hydrogen, copper.
• More reactive metals react more vigorously with water and dilute acids; less reactive metals react slowly or not at all.
• A metal's reactivity reflects how readily it forms a positive ion — the higher in the series, the more readily positive ions are formed.
• Metals below carbon in the series can be extracted by reduction with carbon; metals above carbon require a different method.

The big picture

Metals can be ranked in a reactivity series based on how readily they react with water and dilute acids. The higher a metal sits in the series, the more readily it forms a positive ion, and the more vigorously it reacts. This order — from potassium at the top to copper at the bottom — also determines how metals can be extracted from their ores. The non-metals carbon and hydrogen are placed in the series as reference points.

The reactivity series — from most to least reactive

Read top to bottom: the further down a metal sits, the less readily it reacts with water and acids.

1. 1

   Potassium, Sodium, Lithium

   These three react vigorously with cold water, releasing hydrogen gas. The vigour decreases from potassium (most vigorous, hydrogen ignites with a lilac flame) down to lithium (steady fizzing only). All three are stored under oil to prevent contact with moisture.

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2. 2

   Calcium

   Calcium reacts steadily with cold water — it fizzes, and the water turns milky as calcium hydroxide forms. Less dramatic than the three above it, but still clearly reactive with cold water.

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3. 3

   Magnesium

   Magnesium reacts very slowly with cold water but readily with dilute acids. It is the boundary metal: just below those that react with cold water, but well above those that don't react with acids at all.

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4. 4

   Carbon (non-metal reference point)

   Carbon is not a metal but is placed here as a reference point. Metals below this line can be extracted from their ores by reduction with carbon. Metals above this line cannot — they are too reactive for carbon to displace them.

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5. 5

   Zinc, Iron

   Zinc and iron do not react with cold water, but both react with dilute acids to produce hydrogen gas and a salt. Zinc is above iron and reacts slightly more readily, reflecting its higher position.

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6. 6

   Hydrogen (non-metal reference point)

   Hydrogen is placed here as a reference marker. Metals above this line react with dilute acids and produce hydrogen gas. Metals below this line do not react with dilute acids at all.

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7. 7

   Copper

   Copper is at the bottom and is the least reactive of the named metals. It does not react with cold water or dilute acids. Copper is a useful benchmark: any metal that fails to displace copper in a displacement test is at the very bottom of the series.

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Predict, then check

Think about the positions of both metals in the reactivity series before you commit.

Magnesium ribbon is dropped into iron sulfate solution. Which outcome do you predict?

Tap any cell to reveal it. Tap a column header to read one property down every item.

Memory hook

Please Stop Little Children Making Crazy Zebras In Houses Coloured — the ten words stand in order for K, Na, Li, Ca, Mg, C, Zn, Fe, H, Cu.

Check yourself

Without looking — which metals in the series react with cold water, which react only with dilute acid, and which react with neither?