The Reactivity Series

The reactivity series is a list of metals which are arranged in order of their reactivity. At the top, we have the most reactive metals and the least reactive metals are at the bottom.

  • Carbon and hydrogen are non-metals which are often included in the reactivity series for comparison.

When metals react, they lose electrons to form positive ions (cations).

MM+ + e

How easily a metal loses electrons is a measure of how reactive it is. Therefore, the more easily a metal loses electrons, the higher it is placed in the reactivity series.

Metals at the top of the series oxidise more easily, meaning they lose electrons more readily. Whereas, metals at the bottom of the series are less reactive and are more resistant to oxidation, which means they do not lose electrons easily.

  • More reactive metals tend to have more vigorous reactions compared to less reactive metals.

Reactions of Metals with Water

Some metals react with cold water to form a metal hydroxide and hydrogen gas.

Metal + WaterMetal hydroxide + Hydrogen

For example, lithium reacts with cold water to form lithium hydroxide and hydrogen gas.

Lithium + Water → Lithium hydroxide + Hydrogen

2Li (s) + 2H2O (l)2LiOH (aq) + H2 (g)

Reactions of Metals with Acids

Most metals react with dilute acids, such as HCl, to form a salt and hydrogen.

Metal + AcidMetal salt + Hydrogen

For example, potassium reacts rapidly with dilute hydrochloric acid to form potassium chloride and hydrogen gas.

Potassium + Hydrochloric acid → Potassium chloride + Hydrogen

2K (s) + 2HCl (aq)2KCl (aq) + H2 (g)