How metals occur in nature
Before deciding how to extract a metal, we must know the form in which it occurs in nature.
| Place in the series | Metals | How they occur in nature |
|---|---|---|
| Top | Na, K, Ca | never as free elements; as very stable ionic compounds |
| Middle | Fe, Sn, Zn, Pb | as compounds |
| Bottom | Ag, Au, Pt | as the free metal itself, mixed with other constituents |
The pattern
The more reactive a metal, the more firmly it is locked up as a compound, and the harder that bond is to break. Metals of low reactivity are found with no bond to break at all.
Metal extraction
The definition
Separating a metal from the natural ore that contains it is called metal extraction.
So how much extraction is needed varies from metal to metal: for gold it is only a matter of separating it from other constituents, while for sodium the compound itself must be broken apart.