Aluminum
Symbol: Al
Atomic Number: 13
Atomic Mass: 26.981539 amu
Melting Point: 660.37 C (933.52 K, 1220.666 F)
Boiling Point: 2467.0 C (2740.15 K, 4472.6 F)
Number of Protons: 13
Number of Electrons: 13
Number of Neutrons: 14
Classification: Metal
Crystal Structure: Cubic
Density @ 293 K: 2.702 grams per cubic centimeter
Color: Silver
Alum was used by the Romans in their dyeing processes as well as being used as an astringent. It is from the Latin word for alum “alumen” that the element gets its name.
Aluminum is also called aluminium. In 1807 before its existence had been confirmed Sir Humphry Davy suggested the name alumium for the metal believed to be forming the compound alum. He then agreed to change this to aluminum. Soon after this name was agreed the International Union for Pure and Applied Chemistry IUPAC (the committee who arrange the names of chemicals and elements) changed this to aluminium. The -ium ending brought the element’s name into line with those of many other elements. The element was known as aluminium internationally until 1925 when the American Chemical Society unilaterally reverted back to aluminum. So while the rest of the world calls the element aluminium the Americans call it aluminum.
In 1787 scientists believed there was a metal in the alum compound. It was eventually produced by a Danish chemist called Hans Christian Oersted in 1825. Only very small amounts of the element were available and it was not until 1845 that the German chemist Friedrich Wohler managed to produce enough of the element to ascertain its physical properties. Over a number of years chemists continued to improve the extraction process.
Aluminum was too expensive for general use until the 1880 when two new processes were developed. The first was a method to obtain aluminum from aluminum oxide and was invented in 1886 independently by the American chemist Charles Martin Hall and the French chemist Paul L. T. Heroult. In 1888 the supply of aluminum oxide was greatly increased when the Austrian chemist Karl Joseph Bayer developed a method of extracting aluminum oxide from the mineral bauxite. The Hall-Heroult method and the Bayer method are still used by the aluminum industry today.
The change in supply of aluminum can be charted by its drop in price in 1852 it cost $1200 per kilogram this dropped to $40 by 1859. In 1909 the price of a kilogram of aluminum was $0.60.
Naturally occurring aluminum consists of the stable isotope aluminum-27. There are several unstable isotopes of aluminum. The mass numbers of these isotopes range from 21 to 41.
Aluminum is the most plentiful metal in the earth’s crust but it has never been found as a free element. Aluminum makes up approximately 8.2% of the earth’s crust. Most aluminum is extracted commercially from the mineral bauxite
When manufacturers need a strong light material they often look to aluminum. It is used in a range of items from the cans, foils and utensils used in the kitchen to parts of airplanes and rockets. Although it does not conduct electricity as well as copper wire aluminum wire is often used for overhead power cables because of its light weight. It can also be deposited on glass surfaces to make mirrors. Laser technology uses synthetic rubies made of aluminum oxide.
The biological role of aluminum is still being studied. It may be involved in the action of some enzymes such as succinic dehydrogenase and aminolevulinate dehydrase. Some of the compounds of aluminum are toxic to plant life and some mammals. Aluminum may have been implicated in some cases of Alzheimer’s disease.
