Sunday, December 14, 2008

An elementary guide to minerals

The early Greeks thought that all material on Earth was constructed of a combination of four basic elements: earth, water, air, and fire. Wrong. Centuries later, alchemists looking for the formula for precious metals, such as gold, decided that the essential elements were sulfur, salt, and mercury. Wrong again.
In 1669, a group of German chemists isolated phosphorus, the first mineral element to be accurately identified. After that, things moved a bit more swiftly. By the end of the 19th century, scientists knew the names and chemical properties of 82 elements. Today, 112 elements have been identified.
The classic guide to chemical elements is the periodic table, a chart devised in 1869 by Russian chemist Dmitri Mendeleev (1834–1907), for whom mendelevium was named. The table was revised by British physicist Henry Moseley (1887–1915), who came up with the concept of atomic numbers, numbers based on the number of protons (positively charged particles) in an elemental atom.
The periodic table is a clean, crisp way of characterizing the elements, and if you are now or ever were a chemistry, physics, or premed student, you can testify firsthand to the joy (maybe that’s not the best word?) of memorizing the information it provides. Personally, I’d rather be forced to watch reruns of The Dating Game.

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