What Is the Reactivity Series?

The reactivity series is a list of metals arranged in order of their reactivity, from the most reactive to the least reactive.

This series helps chemists predict how metals will react with water, acids, and other metal compounds.

Highly reactive metals react very easily, while less reactive metals react slowly or not at all.

Reactivity Series of Metals

A simplified reactivity series commonly used in O Level Chemistry is:

Potassium (K)
Sodium (Na)
Calcium (Ca)
Magnesium (Mg)
Aluminium (Al)
Zinc (Zn)
Iron (Fe)
Copper (Cu)
Silver (Ag)
Gold (Au)

Metals at the top of the series are more reactive, while those at the bottom are less reactive.

Reactions of Metals with Water

Highly reactive metals react with cold water.

Examples include:

• Potassium
• Sodium
• Calcium

These metals react quickly to form metal hydroxides and hydrogen gas.

Example reaction:

2Na + 2H₂O → 2NaOH + H₂

Reactions of Metals with Acids

Many metals react with acids to produce:

• Salt
• Hydrogen gas

General reaction:

Metal + Acid → Salt + Hydrogen

Example:

Mg + 2HCl → MgCl₂ + H₂

More reactive metals react more vigorously with acids.

Displacement Reactions

A displacement reaction occurs when a more reactive metal replaces a less reactive metal from its compound.

Example:

Zn + CuSO₄ → ZnSO₄ + Cu

Zinc is more reactive than copper, so it displaces copper from the compound.

Displacement reactions help identify the relative reactivity of metals.

Metals and Oxygen Reactions

Many metals react with oxygen to form metal oxides.

Example:

2Mg + O₂ → 2MgO

Highly reactive metals react rapidly with oxygen, while less reactive metals react slowly.

Importance of the Reactivity Series

The reactivity series helps chemists:

• Predict metal reactions with water and acids
• Understand displacement reactions
• Determine methods of metal extraction
• Study corrosion and metal stability

It is a fundamental concept used in many areas of chemistry.

Exam Tip (5070)

Students are often asked to:

• Arrange metals in the reactivity series
• Predict outcomes of displacement reactions
• Identify metals that react with water or acids

Example exam question:

Which metal can displace copper from copper sulfate solution?

Answer:

Any metal above copper in the reactivity series, such as zinc or iron.

Practice Question

Will copper displace zinc from zinc sulfate solution?

Answer

No. Copper is less reactive than zinc, so it cannot displace zinc from its compound.

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