Argon

 __**Argon**__

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= __**Fast Facts**__ = symbol = Ar atomic number = 18 group = 18 a.k.a. 8 atomic mass = 39.948 Density = 1.784 g/L state at room temperature and pressure =gas boiling point = −185.85 °C, −302.53 °F freezing point = −189.35 °C, −308.83 °F

Argon is colorless, odorless, and nontoxic as a solid, liquid, and gas. Argon is inert under most conditions and forms no confirmed stable compounds at room temperature. Argon is a Noble Gas which means it has a full outer shell of electrons. For while it was thought that Argon could not make any compounds, but In 2000 researchers at the University of Helsinki in Finland found argon was capable of making argon hydrofluorine (HArF), a compound of argon with fluorine and hydrogen although it can only exist at -446 degrees Fahrenheit. In 2009 the molecular ion ArSiF was formed but only exists in the gaseous state.

= = = __**Isolation/ Occurence**__ = Argon is isolated from the air by cryogenic fractional distillation, a process also used for purified nitrogen, oxygen, neon, krypton, and xenon. Argon is formed by the decay of Potassium-40 which forms argon-40. Argon-40 makes up 99% of the earth's atmosphere.

= **__History__** = Argon was first identified by John Strutt and Sir William Ramsay. They discovered argon beacause they found that two samples of nitrogen had different densities when one was extracted from the air and when it was detained by decomposing ammonia. To solve their problem Ramsay passed heated magnesium over the air sample which formed magnesium nitride. He was left with about 1% also. He measured the density and found it was denser than Nitrogen. By examining the spectrum they realized they had discovered a new gas. They named it argon from the Greek word //argos// meaning "lazy" or "inactive." However, this was not the first encounter. In 1785 Henry Clavendish passed electric sparks through a sample of air and hydrogen and trapped the gasses that formed but did not know what the 1% remainder was. In 1882 Hugh Frank Newall and Walter Noel Hartley recorded new lines in the spectrum of air when they photographed it at low pressure.

= __Most Common Isotopes in the Armoshphere:__ =
 * Isotope || number of neutrons || % in air ||
 * Ar-36 || 18 || 0.34 ||
 * Ar-38 || 20 || 0.06 ||
 * Ar-40 || 22 || 99.6 ||

= __**Uses**__ =
 * Argon is used as an insulator to surround reactive gasses when Nitrogen is not sufficient
 * welding
 * extinguishing fires
 * slaughtering of poultry
 * preservation of food and objects. It slows the decay from oxidation and moisture.
 * destroying cancer cells, correcting defects of the eye, and to weld arteries
 * surrounds the filament of the incandescent light bulb and prevents the filament from oxidation.
 * between window panes because argon is not a good conductor of heat
 * inflate diving suits
 * luxury tires

= __** Fun Facts **__ =
 * Argon was the first Noble Gas to be discovered
 * Argon is the least expensive Noble Gas
 * The Declaration of Independence and the Constitution are encased in Argon-filled
 * 56th most abundant gas
 * originally the symbol for argon was A but it was changed in 1957cases to retard their degradation
 * 1.6% of Mar's atmosphere is argon, and Mercury's atmosphere is made mostly of argon
 * argon is as soluble in water as oxygen
 * argon is slightly more abundant in the air nearer to earth

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== = = = = = __**Sources**__ = "Air Distillation." __Wikipedia.__ 26 Nov. 2011. <[]> "Argon." __Wikipedia.__ 26 Nov. 2011 "Argon: the essentials." __Web Elements__. 30 Nov. 2011. [] <[]> Emsley, John. "Argon." __Nature's Building Block: An A-Z Guide to the Elements__. Oxford University Press Inc., 2011. "Fractionation" __Wikipedia.__ 26 Nov. 2011 <[]> Stwertka, Albrt. "Argon" __A Guide to the Elements.__ Oxford University Press Inc., 2nd edition.