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Characteristics:
Aluminum is a silvery-white metal. It is non-magnetic and an excellent electrical conductor. It is of low density and high ductility. It is too reactive to be commonly found as the metal although, very rarely, the native metal can be found. (5)
Aluminum's appearance is dulled and its reactivity is passivated by a film of aluminum oxide that naturally forms on the surface of the metal under normal conditions. The oxide film results in a material that resists corrosion. The film can be thickened using electrolysis or oxidizing agents and aluminum in this form will resist attack by dilute acids, dilute alkalis and concentrated nitric acid.
Aluminum lies sufficiently far on the right side of the periodic table that it shows some hints of nonmetal behavior, reacting with hot alkalis to form aluminate ions [Al(OH)4]- as well as the more typical metal reaction with acids to release hydrogen gas and form the positively charged metal ion, Al3+. I.e. aluminum is amphoteric.
Pure aluminum is quite soft and lacking in strength. Aluminum used in commercial applications has small amounts of silicon and iron (less than 1%) added, resulting in greatly improved strength and hardness.