The Reactivity Series and Electrolysis

The reactivity series

Most → least reactive:

Potassium, Sodium, Lithium, Calcium, Magnesium, Aluminium,
(Carbon), Zinc, Iron, (Hydrogen), Copper, Silver, Gold

Displacement reactions

A more reactive metal displaces a less reactive one from its compound:

iron + copper sulfate → iron sulfate + copper

Extracting metals

• Metal less reactive than carbon (zinc, iron, copper) → extracted by reduction with carbon.
• Metal more reactive than carbon (aluminium and above) → extracted by electrolysis (carbon can't displace it).

Oxidation and reduction (OIL RIG)

Oxidation Is Loss, Reduction Is Gain — of electrons.

Electrolysis

Splitting an ionic compound (molten or in solution) using electricity:

Cathode (−): positive ions gain electrons (REDUCTION) → metal/hydrogen
Anode (+):   negative ions lose electrons (OXIDATION) → non-metal

Example (molten lead bromide): lead forms at the cathode, bromine at the anode.

Exam tip

Reactive metals (above carbon) need electrolysis; less reactive ones can be reduced by carbon. Remember OIL RIG and that the cathode is negative.