Activity Series of Metals Cheat Sheet

Key Facts

• A metal higher in the activity series is more reactive and can replace a metal lower in the series from an aqueous ionic compound.
• The general single-displacement pattern is $A + BC \rightarrow AC + B$ when metal $A$ is more reactive than metal $B$.
• If metal $A$ is lower than metal $B$ in the activity series, the reaction $A + BC \rightarrow$ products does not occur.
• Metals above hydrogen react with acids to form a salt and hydrogen gas, such as $Zn + 2HCl \rightarrow ZnCl_2 + H_2$.
• Metals below hydrogen, such as copper, silver, gold, and platinum, usually do not produce $H_2$ gas with dilute acids.
• In a successful displacement reaction, the solid metal loses electrons and is oxidized, such as $Zn \rightarrow Zn^{2+} + 2e^-$.
• The metal ion being displaced gains electrons and is reduced, such as $Cu^{2+} + 2e^- \rightarrow Cu$.
• A balanced equation must conserve atoms and charge, so $2Al + 3CuCl_2 \rightarrow 2AlCl_3 + 3Cu$ is balanced correctly.

Vocabulary

Activity series

A list of metals arranged from most reactive to least reactive based on their ability to lose electrons.

Single-displacement reaction

A reaction in which one element replaces another element in a compound, often written as $A + BC \rightarrow AC + B$.

Oxidation

The loss of electrons by an atom or ion, such as $Mg \rightarrow Mg^{2+} + 2e^-$.

Reduction

The gain of electrons by an atom or ion, such as $Ag^+ + e^- \rightarrow Ag$.

Spectator ion

An ion that remains unchanged during a reaction and does not take part in the electron transfer.

Hydrogen gas test

A test in which hydrogen gas makes a small pop sound when exposed to a flame, showing that $H_2$ was produced.