![Aluminium bar surface etched.jpg](https://upload.wikimedia.org/wikipedia/commons/thumb/e/e1/Aluminium_bar_surface_etched.jpg/300px-Aluminium_bar_surface_etched.jpg)
Aluminium is a chemical element; it has symbol Al and atomic number 13. Aluminium has a density lower than that of other common metals; about one-third that of steel. It has a great affinity towards oxygen, forming a protective layer of oxide on the surface when exposed to air.
Aluminium is used in a huge variety of products including cans, foils, kitchen utensils, window frames, beer kegs and aeroplane parts. This is because of its particular properties.