Metals are found in the Earth's crust. Rocks that contain the metals are called ores.
Unreactive metals are found as elements because they are pure and not mixed with any other element such as oxygen e.g. gold- these do not need to be separated
Reactive metals are found as compounds because they are mixed with another element like oxygen e.g. lead oxide
Anything above carbon in the reactivity series is extracted by electrolysis.
Anything below copper is extracted as it is- found pure and on their own
Anything below carbon and above copper is separated with carbon
It depends on two reasons why a metal should be extracted:
1) how easy it is to extract it from its ore
2) how much metal the ore contains
How do we extract metals?
It depends where the metal is in the reactivity series to how you extract it
A more reactive metal will displace a less reactive metal from its compound
Carbon (non-metal) will displace less reactive metals from their oxides
We can heat the metal oxide with carbon, the carbon removes the oxygen from the metal oxide to form carbon dioxide leaving the metal separated
metal oxide + carbon = metal + carbon dioxide
lead oxide + carbon = lead + carbon dioxide
PbO + C = Pb + CO2
We call the removal of oxygen from a compound chemical reduction!