Chemical Changes: The Reactivity Series

The Reactivity Series

In the Reactivity Series, metals are ordered according to how willing they are to lose electrons and react with other substances.
This series aids in predicting chemical reactions, particularly displacement reactions.
The most reactive metals, such as potassium and sodium, are found at the top, while the least reactive, including gold and silver, are at the bottom.
A key point to remember is that metals higher up in the series will displace metals that are lower down.

Reactivity with Air and Water

Metals react with oxygen to form metal oxides in a process known as oxidation. This can lead to corrosion in metals such as iron.
Some metals react with water. Fast reactions produce hydrogen, seen in the form of fizzing or bubbles, and the metal hydroxide.
For example, the reaction of calcium with water produces calcium hydroxide and hydrogen.

Displacement Reactions

A displacement reaction occurs when a more reactive metal displaces a less reactive metal from its compound.
For example, magnesium can displace copper from copper sulfate, forming magnesium sulfate and copper. This because magnesium is higher than copper in the Reactivity Series.

Extraction and Use of Metals

The method of extraction for a metal is based on its position in the Reactivity Series.
Metals below carbon in the series can be extracted from their ores by reduction with carbon. For example, iron ore is reduced in a blast furnace to make iron.
Metals that are above carbon must be extracted using electrolysis, which is more costly.
Understanding the Reactivity Series guides the use of metals. For instance, metals that don’t corrode easily, like gold, are used to make jewellery.

Reactivity Series Test

The Reactivity Series can be explored through practical experiments.
When a small piece of a metal is put into a solution of a compound of another metal, if a reaction occurs, it indicates that the metal is more reactive.
These experiments provide an understanding of how metals displace other metals based on their reactivity.