1. Highly active metals like potassium, sodium, calcium, magnesium and aluminium are obtained by the electrolysis of their fused halides or oxides, that is, by electrolytic reduction because their oxides cannot be reduced by common reducing agents like carbon, carbon monoxide and hydrogen.
2. Zinc is obtained only by heating its oxide with carbon.
3. Iron, lead and copper are obtained by reduction of their oxides with carbon, carbon monoxide and hydrogen.
4. Copper is obtained by reducing black copper oxide with carbon or by air reduction.
5. Mercury and silver are obtained by heating their respective oxides to temperature above 300°C when they lose oxygen and are reduced to free metals.
6. However, less active mercury can also be obtained by merely heating its sulphide in air.
7. Silver and Gold are obtained by displacement from solutions containing their ions by more electropositive metal zinc.
