The Reactivity Series

This lesson covers the reactivity series of metals as required by the Edexcel GCSE Combined Science specification (1SC0). You need to know the order of metals in the reactivity series, predict reactions based on it, and understand how to use experimental observations to determine a metal's position.

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What Is the Reactivity Series?

The reactivity series is a list of metals arranged in order of their reactivity — from the most reactive at the top to the least reactive at the bottom. It also includes carbon and hydrogen as important reference points.

graph TD
    subgraph Reactivity Series
        K["Potassium (K) — Most reactive"]
        Na["Sodium (Na)"]
        Li["Lithium (Li)"]
        Ca["Calcium (Ca)"]
        Mg["Magnesium (Mg)"]
        Al["Aluminium (Al)"]
        C_["(Carbon)"]
        Zn["Zinc (Zn)"]
        Fe["Iron (Fe)"]
        H_["(Hydrogen)"]
        Cu["Copper (Cu)"]
        Ag["Silver (Ag)"]
        Au["Gold (Au)"]
        Pt["Platinum (Pt) — Least reactive"]
    end

    K --> Na --> Li --> Ca --> Mg --> Al --> C_ --> Zn --> Fe --> H_ --> Cu --> Ag --> Au --> Pt

    style K fill:#c0392b,color:#fff
    style Na fill:#e74c3c,color:#fff
    style Li fill:#e67e22,color:#fff
    style Ca fill:#f39c12,color:#fff
    style Mg fill:#f1c40f,color:#000
    style Al fill:#2ecc71,color:#fff
    style C_ fill:#1abc9c,color:#fff
    style Zn fill:#3498db,color:#fff
    style Fe fill:#2980b9,color:#fff
    style H_ fill:#9b59b6,color:#fff
    style Cu fill:#8e44ad,color:#fff
    style Ag fill:#7f8c8d,color:#fff
    style Au fill:#95a5a6,color:#fff
    style Pt fill:#bdc3c7,color:#000

Remembering the Order

A common mnemonic for the reactivity series is:

Please Stop Letting Careless Monkeys Always Carry Zinc In Huge Copper Silver Gold Pots

(Potassium, Sodium, Lithium, Calcium, Magnesium, Aluminium, Carbon, Zinc, Iron, Hydrogen, Copper, Silver, Gold, Platinum)

Exam Tip: Carbon and hydrogen are included in the reactivity series even though they are not metals. Carbon is important for extraction of metals; hydrogen helps us predict which metals react with acids.

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Reactions of Metals with Water

The most reactive metals react vigorously with cold water; less reactive metals may react with steam but not cold water; unreactive metals do not react at all.

Reactions with Cold Water

metal + water → metal hydroxide + hydrogen

Metal	Observation	Equation
Potassium	Floats, catches fire (lilac flame), moves rapidly, melts into a ball	2K + 2H₂O → 2KOH + H₂
Sodium	Floats, fizzes vigorously, melts into a shiny ball, moves around	2Na + 2H₂O → 2NaOH + H₂
Lithium	Floats, fizzes steadily, moves slowly	2Li + 2H₂O → 2LiOH + H₂
Calcium	Sinks then floats (bubbles of H₂ lift it), fizzes, water turns milky	Ca + 2H₂O → Ca(OH)₂ + H₂

Reactions with Steam

Metals below calcium but above hydrogen react with steam:

metal + steam → metal oxide + hydrogen

Metal	Equation
Magnesium	Mg + H₂O → MgO + H₂
Zinc	Zn + H₂O → ZnO + H₂
Iron	3Fe + 4H₂O → Fe₃O₄ + 4H₂

Exam Tip: Metals below hydrogen in the reactivity series (copper, silver, gold) do not react with water or steam.

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Reactions of Metals with Dilute Acids

Metals above hydrogen in the reactivity series will react with dilute hydrochloric or sulfuric acid:

metal + acid → salt + hydrogen

Metal	Observation	Equation (with HCl)
Magnesium	Rapid fizzing, dissolves quickly, warm	Mg + 2HCl → MgCl₂ + H₂
Zinc	Steady fizzing, dissolves slowly	Zn + 2HCl → ZnCl₂ + H₂
Iron	Slow fizzing, very slow to dissolve	Fe + 2HCl → FeCl₂ + H₂
Copper	No reaction	—

Key Observations

• The more reactive the metal, the faster the reaction (more vigorous fizzing).
• Metals below hydrogen (copper, silver, gold, platinum) do not react with dilute acids.
• The gas produced (hydrogen) can be tested with a burning splint — squeaky pop.

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Reactions of Metals with Oxygen

Metals react with oxygen to form metal oxides:

metal + oxygen → metal oxide

Metal	Observation When Heated in Air	Product
Magnesium	Burns with a bright white flame	White MgO powder
Iron	Glows and produces sparks (iron wool)	Black Fe₃O₄
Copper	Surface turns black slowly	Black CuO
Gold	No reaction	—

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Using the Reactivity Series to Make Predictions

The reactivity series allows you to predict:

1. Which metals react with water, steam or acid — and how vigorously.
2. Displacement reactions — a more reactive metal will displace a less reactive metal from its compound.
3. Extraction methods — metals above carbon need electrolysis; metals below carbon can be extracted by reduction with carbon.

Prediction	Rule
Will the metal react with dilute acid?	Only if the metal is above hydrogen in the reactivity series
Will metal A displace metal B from a solution?	Only if metal A is more reactive than metal B
How is the metal extracted from its ore?	Above carbon → electrolysis; below carbon → reduction with carbon

Exam Tip: Questions often give you observations and ask you to rank metals by reactivity. The faster and more vigorous the reaction with acid or water, the higher the metal is in the reactivity series.

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Summary

• The reactivity series ranks metals from most reactive (potassium) to least reactive (platinum).
• Carbon and hydrogen are included as reference points.
• Reactive metals react vigorously with water and dilute acids; unreactive metals do not react.
• The series helps predict displacement reactions and extraction methods.
• Metals above hydrogen react with dilute acids to produce a salt and hydrogen gas.
• Metals above carbon are extracted by electrolysis; metals below carbon are extracted by reduction with carbon.

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Worked Example: Ranking Unknown Metals from Experimental Data

A student tests four unknown metals (A, B, C, D) with dilute hydrochloric acid at the same concentration and temperature. The volume of hydrogen gas produced in 60 seconds is recorded.