The Noble Cases

Although the chemistry of the noble gases has been of recent development, the noble gases themselves have been known for many years. For example, radon, which occurs only as a product of radioactive decay, has been known for over a century. 

In 1868, Lockyer and Frankland identified helium in the spectrum of the sun on the basis of its spectral lines. In 1894, helium was found in uranium ore, where it is produced by the decay of U as shown by the following equation  

The a particles (helium nuclei) acquire two electrons to become helium atoms, some of which remain trapped in the ores. The Greek word for sun, helios, is the origin of the name helium. 

Ra is produced, and it decays by a emission to produce Rn that has a half-life of 3.825 days. Although the entire decay schemes will not be shown, the relevant steps that lead to the production of radon can be summarized as follows  

The radioactive decay of the three radon isotopes after they are produced can be shown as follows  

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Properties of the Group 18 (VIHA) Elements The Noble Cases... 

TABLE 11.3 Boiling Points of the Halogens and the Noble Cases ... 

Applications of the Noble Cases Neon, Krypton and Xenon... 

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