Argon: The First Noble Gas

Argon: The First Noble Gas

The noble gases are chemical elements with similar properties that are all odorless, colorless, monatomic gases with very low chemical reactivity under standard conditions. The six noble gases that occur naturally are helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). Helium, neon and radon are pretty widely known in everyday conversation because of balloons, bright flashy signs and the threat of radioactive gas in homes. Krypton is used in Imax cinema projectors because it works well in an arc to create huge images from a tiny light source and Xenon is commonly used in high efficiency light bulbs before LED became a better choice. Like Krypton and Xenon, Argon is not talked about in everyday conversations but it is probably the most useful gas of them all. It is used with nitrogen in the incandescent light bulb, used in energy efficient windows, and used to preserve the Declaration of Independence and the Constitution at the U.S. National Archives. There lots of other uses of course but even with bulbs, windows and two of the country’s most important documents, people do not recognize Argon the way they do helium, neon and radon.

Argon was discovered in 1895 by William Ramsay and Robert John Strutt (also known as Lord Rayleigh). They were following up on a problem first discovered by Henry Cavendish in 1785 when he found that an unknown gas still existed even after oxygen and nitrogen were removed from air (Pauling, 256). Rayleigh first ran two tests to measure the density of nitrogen and the test produced very small differences in the results (Giunta, 3). He did not just consider it an insignificant error even thought it was very small. He kept at it and together they ran many tests with elements and as many substances as they could until concluding that the new gas did not react with anything and was inert. Argon was the first noble gas discovered and of course there was no place to put it on the periodic table which must have caused a lot of suspicion among scientists. It was given the symbol A up until 1957 when it was changed to Ar. There was also a belief that if there was Argon, then there were probably other noble gasses. Rayleigh and Ramsay won Noble prizes in 1904 but Rayleigh won it just for Argon. Ramsay went on to discover neon, krypton and xenon and won the prize for that as well.

Argon is a chemical element with symbol Ar and atomic number 18. It is the third most common gas in the Earth's atmosphere, at 0.93% (9,300 ppm), making it about 23.8 times carbon dioxide (390 ppm), and more than 500 times the next most common noble gas which is neon (18 ppm) and Argon comes from decay of Potassium in the earth’s crust (Pauling, 246). It is a noble gas because it will almost never form compounds with another noble gas or with any other elements.