Reactivity series Revision Notes for AQA GCSE Chemistry

Reactivity series

What is the reactivity series?

infoNote

The reactivity series is a fundamental concept in chemistry that shows metals arranged in order of how easily they react.

When metals react, they lose electrons to become positive ions. The easier it is for a metal to form positive ions, the more reactive that metal is.

Scientists work out this order by testing how metals react with water and dilute acids. This experimental approach allows us to compare the relative reactivity of different metals under controlled conditions.

The reactivity series order

Here are the metals in order from most reactive to least reactive:

Most reactive:

Potassium - fizzes violently with water and acid
Sodium - fizzes quickly with water and acid
Lithium - fizzes steadily with water and acid
Calcium - fizzes with water, bubbles quickly with acid
Magnesium - fizzes very slowly with water, bubbles quickly with acid

Less reactive:

Carbon - no reaction with water or acid
Zinc - no reaction with water, fizzes with acid
Iron - no reaction with water, fizzes very slowly with acid
Hydrogen - included for comparison
Copper - no reaction with water or acid

Least reactive

chatImportant

The metals at the top are much more dangerous to handle than those at the bottom due to their violent reactions with water and acids.

How metals react with water and acids

Reactive metals follow two main patterns when they undergo chemical reactions:

With water:

Metal + water → metal hydroxide + hydrogen gas
Example: $\text{lithium + water} \rightarrow \text{lithium hydroxide + hydrogen}$

With dilute acids:

Metal + acid → metal salt + hydrogen gas
Example: $\text{magnesium + hydrochloric acid} \rightarrow \text{magnesium chloride + hydrogen}$

The hydrogen gas produced makes the fizzing or bubbling you see during these reactions. This gas can be collected and tested - it makes a squeaky pop when lit with a burning splint.

Displacement reactions

A more reactive metal can push out (displace) a less reactive metal from its compound. This is one of the most important applications of the reactivity series.

chatImportant

The rule: More reactive metals displace less reactive metals.

lightbulbExample

Worked Example: Displacement Reactions

Example 1: Zinc displaces copper $\text{zinc + copper sulfate} \rightarrow \text{zinc sulphate + copper}$

Example 2: Magnesium displaces hydrogen
$\text{magnesium + sulfuric acid} \rightarrow \text{magnesium sulphate + hydrogen}$

Example 3: Carbon displaces zinc $\text{carbon + zinc oxide} \rightarrow \text{zinc + carbon dioxide}$

This happens because the more reactive metal forms positive ions more easily. The less reactive metal is forced out of its compound and appears as the pure metal.

bookmarkSummary

Key Points to Remember:

Metals are arranged by reactivity - how easily they form positive ions
Most reactive metals are at the top - potassium, sodium, lithium
Least reactive metals are at the bottom - copper is very unreactive
More reactive metals displace less reactive ones from compounds
All metal reactions with acids produce hydrogen gas - this causes the fizzing

Reactivity series (AQA GCSE Chemistry): Revision Notes