Krypton, Neon, and Xenon

The discoveries of argon and helium are remarkable also in that they set the chemists thinking not only about the nature of chemical inertness (the phenomenon was understood only about a quarter of a century later) but about the 

History has a striking power of prediction. Argon had not been properly discovered yet, when on May 24, 1894, Ramsay wrote a letter to Rayleigh in which he asked whether it had ever occurred to him that there was indeed a place in the periodic table for gaseous elements. For instance  

And here again we see the same certainty which permeated Ramsay s letter to his wife on the eve of argon s discovery. But now it was not audacity of a romantic but conviction multiplied by experience. The undiscovered gas turned out to be neon. Owing to a whim of fate (a frequent thing in 

The discovery of neon promptly followed. Ramsay and Travers selected light fractions formed on the distillation of air and discovered a new inert gas in one of them. Ramsay later recollected that the name neon (from the Greek neOs for new ) had been proposed hy Ramsay s twelve-year-old son. In this case the experiment was performed hy Travers alone since Ramsay was away. It was on the 7th of June. Then a whole week was required to confirm the results, obtain greater amounts of neon, and determine its density. Neon, as had been expected, turned out to be an intermediate between helium and argon although it had not yet been isolated as a pure gas. The problem of complete separation of neon and argon was solved later. 

Still another inert gas was to be discovered by Ramsay and Travers. The scientists, however, did not feel as certain as in the case of neon. One day in July, 1898, the colleagues were busy with distilling liquid air and separating it into fractions. By midnight they collected more than 50 fractions 

By this time Ramsay and his colleague had a new liquid-air machine from which they could get larger and larger quantities of krypton and neon. Repeated fractionations produced a heavier gas that produced a beautiful blue in their discharge tubes. They called it xenon (from the Greek xenos, for strange ). 

In 1904 a most unusual Nobel Prize ceremony occurred. The winner m physics for his work on the densities of gases and the discovery of argon was Lord Rayleigh. 

The winner in chemistry for his work in discovering the first five inert gaseous elements in air and their place in the periodic table was William Ramsay. Sometimes the divisions between these two sciences are very small indeed. 

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Sir William Ramsay, 1852-1916. Scottish chemist and physicist. Discoverer of the inert gases. Lord Rayleigh was a co-discoverer of argon, and M. W. Travis collaborated in the discovery of krypton, neon, and xenon. After F. E. Dorn had discovered radon, or radium emanation, Ramsay and Whidaw Gray determined its density and proved it to be the heaviest member of the argon family. 

English chemists Sir William Ramsay and Morris Travers discover krypton, neon, and xenon. 

Atnwspheric gases means air, nitrogen, oxygen, argon, krypton, neon and xenon. US 171.8... 

Within two years, terrestrial helium had been discovered, and the problem became one of accommodating two elements, namely, argon and helium. A further three years were to pass before the discovery of krypton, neon, and xenon. A whole new family of elements had been discovered without having been predicted, and the accommodation of these new elements into the periodic table was proving to be far from trivial. Indeed, it presented a severe threat to the survival of Mendeleev s system. 

Curie discover the elements radium and polonium. Marie Curie coins the term radioactivity after her study of these elements. Scottish chemist William Ramsay and English chemist Morris William Travers discover the elements krypton, neon, and xenon. Scottish chemist Sir James Dewar produces liquid hydrogen. 

The cryogenic fractional distillation of large quantities of atmospheric air is the only practical means available for acquiring the rare gases krypton, neon, and xenon. The recovery of crude rare gases is accomplished in multiple cryogenic fractional distillation columns and... 

Krypton, neon, and xenon are rare atmospheric gases. Each is odorless, colorless, tasteless, nontoxic, monatomic, and chemically inert. All three together constitute less than 0.002 percent of the atmosphere with approximate concentrations in the atmosphere of 18 ppm for neon, 1.1 ppm for krypton, and 0.09 ppm for xenon. Few users of the three gases need them in bulk quantities, and the three are shipped most often in single cylinders and glass liter flasks. 

Under present regulations, cylinders of all types authorized for service with neon, krypton, and xenon must be requalified by hydrostatic test every 5 years with the following exceptions DOT-3A and 3AA used exclusively for krypton, neon, and xenon may be retested every 10 years under special requirements as given in 49 CFR 173.34(e)(15), or equivalent TC regulations [5, 6]. DOT-4 may be retested every 10 years and DOT-3C, 3E, and 4C require no periodic retest. 

The noble gases were all discovered during the last decade of the nineteenth century. In 1894, Lord Rayleigh and William Ramsay isolated a new constituent of the air, which they formally called argon in 1895. Helium was first observed in the solar spectrum but was isolated from a uranium mineral by Ramsay in 1895. Krypton, neon, and xenon were obtained by the fractionation of liquid air by Ramsay and Travers in 1898. Rutherford found one radon isotope (Rn-220), the thorium emanation, in 1899, and Dom found another (Rn-222), the radium emanation, in 1900. Ramsay isolated and determined the density of this highly radioactive gas in 1908. 

In 1895, Ramsay found helium in a uranium mineral. Then, in 1898, by liquefying samples of his argon and carefully distilling the liquid, he obtained not just a purer argon, but, in quick succession, krypton, neon and xenon, which were present as very minor contaminants. 

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