Aluminum is familiar to most everyone. Airplanes are made from aluminum, as are pop cans (soda cans if you prefer), garbage cans, bicycles. It has several advantages that make it ideal for such applications. For one, it is a fairly common metal. It has good strength properties, and is lightweight (compared to many other metals). It is easily recycled, and endures weather well. Unlike iron, which rusts away, when aluminum oxidizes, the aluminum “rust” – aluminum oxide – forms a protective surface layer that prevents the rest of the aluminum from deteriorating.
Aluminum is also a good conductor of heat and electricity. It is a popular choice for cookware as a result. It is also used in ductwork, where it allows heat to disperse quickly (so you don’t get burned by accident) and doesn’t sag from its own weight. For a brief time period, people thought that it would make a good substitute for copper as wiring in homes. The idea made sense, as it was cheaper and conducted well. It turned out to be less than ideal, as the aluminum wiring had a tendency to melt, causing shorts and fires. Those rare houses which still have aluminum wiring can be bought cheaply compared to a matching house with copper wires. On the down side, such homes come with the added expense of having to replace the wiring.
The aluminum ion is notable for being one of the smallest ions there is, having a +3 charge and very little shielding effect between the innermost electrons and the remaining second level octet. Put simply, the remaining electrons are drawn in tightly, making it even smaller than the magnesium or sodium ions. With a +3 charge, it forms less common ionic compounds. While it can make binary (only two elements) pairings, it will often pair up with another ion (like potassium) which has a +1 charge, allowing it to balance evenly charged negative ions (anions) more easily. (An example is aluminum potassium sulfate, or alum.)
Aluminum has but one isotope, with an atomic mass of 26.982 amu.* Each aluminum atom has 13 protons, 14 neutrons, and 13 electrons.
It melts at a mere 660.32 degrees Celsius – low for a metal, and the reason aluminum wires melted so readily. Aluminum boils at 2519 Celsius.
The density of aluminum 2.70 g/cc makes it clear just how light a metal it truly is. Less than three times the density of water, it’s little wonder that rowboats and canoes are also made from aluminum.
Aluminum’s electron configuration is 1s2, 2s2, 2p6, 3s2, 3p1 (or [Ne]. 3s2, 3p1 for short). It is the 3s and 3p electrons that are stripped away to make the ion.
* Numerical Data obtained from the 82nd edition of the CRC Handbook of Chemistry and Physics.
