Electrolysis key terms

cathode

The negative electrode in an electrolysis cell where positive ions are attracted, gain electrons, and are discharged as neutral atoms or molecules.

anode

The positive electrode in an electrolysis cell where negative ions are attracted, lose electrons, and are discharged as neutral atoms or molecules.

Electrolysis

The process of using electrical energy to split an ionic compound into its constituent ions, allowing ions to move to electrodes and be discharged as products.

Aluminium extraction

The industrial process of producing aluminium metal by electrolysing molten aluminium oxide dissolved in cryolite, rather than reducing it with carbon.

aluminium oxide

The aluminium compound used in the extraction of aluminium through electrolysis. In Using electrolysis to extract metals, this term helps explain describe aluminium oxide as the aluminium compound used in extraction for AQA GCSE Chemistry 8462 Unit 4.4.

electrolysis

The process of splitting up an ionic compound using electricity. In Using electrolysis to extract metals, this term helps explain describe aluminium oxide as the aluminium compound used in extraction for AQA GCSE Chemistry 8462 Unit 4.4.

aluminium oxide

The aluminium compound used in the extraction of aluminium through electrolysis. In Using electrolysis to extract metals, this term helps explain explain why aluminium oxide is dissolved in molten cryolite during extraction for AQA GCSE Chemistry 8462 Unit 4.4.

molten cryolite

A substance used to dissolve aluminium oxide to reduce the melting point and improve conductivity during aluminium extraction.

cathode

The negative electrode where reduction occurs, and aluminium ions gain electrons to form aluminium.

aluminium ions

Positively charged ions formed from aluminium that gain electrons at the cathode during electrolysis.

anode

The positive electrode where oxidation occurs during electrolysis. In Using electrolysis to extract metals, this term helps explain describe oxide ions losing electrons at the anode to form oxygen for AQA GCSE Chemistry 8462 Unit 4.4.

oxide ion

A negatively charged ion formed when oxygen gains electrons. In Using electrolysis to extract metals, this term helps explain describe oxide ions losing electrons at the anode to form oxygen for AQA GCSE Chemistry 8462 Unit 4.4.

Carbon anode

The electrode made of carbon that supplies electrons to the electrolyte during aluminium extraction and is consumed as it is oxidised to CO₂.

Aluminium extraction

The industrial process of producing aluminium metal by electrolytic reduction of molten aluminium oxide in an electrolytic cell.

aluminium extraction

The process of obtaining aluminium from its ore using electrolysis. In Using electrolysis to extract metals, this term helps explain write word equations for the main reactions in aluminium extraction for AQA GCSE Chemistry 8462 Unit 4.4.

word equation

A representation of a chemical reaction using the names of the reactants and products.

Aluminium ion reduction

The half‑equation showing Al³⁺ gaining three electrons to form aluminium metal at the cathode.

Oxide ion oxidation

The half‑equation showing O²⁻ losing two electrons to form oxygen gas at the anode.

aqueous solution

A solution in which water is the solvent and contains ions from the dissolved ionic compound, as well as hydrogen ions and hydroxide ions from water.

hydroxide ion

A negatively charged ion (OH-) formed when water dissociates, present in aqueous solutions.

cathode

The negative electrode where reduction occurs during electrolysis. In Electrolysis of aqueous solutions, this term helps explain predict that hydrogen is produced at the cathode if the metal is more reactive than hydrogen for AQA GCSE Chemistry 8462 Unit 4.4.

reactivity series

A list of metals arranged in order of decreasing reactivity, used to predict products in electrolysis.

cathode

The negative electrode where reduction occurs during electrolysis, and where a metal is produced if it is less reactive than hydrogen.

hydrogen

A non-metal element that is produced at the cathode during electrolysis if the metal is more reactive than hydrogen.

anode

The positive electrode where oxidation occurs during electrolysis. In Electrolysis of aqueous solutions, this term helps explain predict that oxygen is produced at the anode unless the solution contains halide ions for AQA GCSE Chemistry 8462 Unit 4.4.

oxygen

A gas produced at the anode during electrolysis of aqueous solutions unless halide ions are present.

halide ion

An ion derived from a halogen that can participate in electrolysis, producing halogen gas at the anode.

anode

The positive electrode in electrolysis where oxidation occurs and halide ions are discharged to form halogen gas.

aqueous electrolysis

The process of using electricity to drive a chemical reaction in a solution containing ions.

reactivity series

A list of metals arranged in order of decreasing reactivity, used to predict products of electrolysis.