1Section 1 of 1About 1 min
Metals, Minerals and Ores
Why metals occur in different forms
- The Earth’s crust is the principal natural source of metals and their compounds.
- Oxygen is the most abundant element in the Earth’s crust, followed by silicon; aluminium is the most abundant metal in the crust.
- Silicon is a metalloid, not a typical metal or non-metal. It shows properties of both groups.
- The natural form of a metal depends mainly on its chemical reactivity:
- Highly reactive metals such as potassium, sodium, calcium, magnesium and aluminium occur only as compounds.
- Moderately reactive metals such as zinc, iron, tin and lead usually occur as oxides, sulphides or carbonates.
- Least reactive metals such as gold and platinum may occur in the native or free state.
- Copper and silver can occur in both native and combined states.