Aluminum Facts: 21-25 | Characteristics of Aluminum
21. The thin film of aluminum oxide that forms on pure aluminum when left in open air can be easily thickened using oxidizing agents or electrolysis. Once the film is thickened, it makes aluminum resistant to concentrated nitric acid, dilute alkalis and dilute acids.
22. Aluminum is pretty unique. It displays properties of both metals and non-metals. It behaves like typical metals when it reacts with acids and produced hydrogen and Al3+ (a positively charged metal ion).
23. It also reacts with hot alkalis and behaves like non-metals forming aluminate ions [Al(OH)4]–. Because aluminum behaves both like metals and non-metals, it is known as amphoteric.
24. In case you didn’t know (or perhaps you have already observed from the first table above), aluminum is actually pretty soft and lacks strength. On Mohs scale, it has a hardness of 2.8
25. So, in order to make use of aluminum in commercial applications, the element is always mixed with small amounts of iron and silicon (less than 1%). This improves the strength and hardness of the metal significantly and hence, makes it usable in commercial applications.
Aluminum Facts: 26-30 | Abundance and Beyond Earth
26. Aluminum is really abundant. In Earth’s crust, this element makes up 8.23% by weight. In terms of moles, it makes up 6.32% of crust of Earth.
27. In entire solar system, abundance of aluminum is 56 ppm by weight and in terms of moles it has an abundance of 2.7 ppm.
28. Wondering just how much those figures mean? In Earth’s crust, it THE MOST ABUNDANT METAL. If we look at MOST ABUNDANT ELEMENT in Earth’s crust, aluminum takes the third spot just after oxygen and silicon.
29. We mentioned earlier that aluminum is too reactive to be obtained in pure form in Earth’s crust. It is actually found in form of various compounds of which aluminum oxide or alum is the most abundant ore.
30. Aluminum is also produced in heavy stars. It is formed during fusion reactions in which magnesium is known to pick up an additional proton to form aluminum. Magnesium in turn is first produced by fusion reaction is stars where two carbon atoms fuse together to form magnesium.