Discovery of The Noble Gasses.

In the late 1800s Johan William Strut, Third Baron of Rayleigh who was a professor of physics at the Cavendish Laboratory in Cambridge, England, accurately determined the atomic masses of a number of elements, but he obtained puzzling results with nitrogen. One of his methods of preparing nitrogen was by thermal decomposition of ammonia.

Another method was to start with air and remove from its oxygen, carbon dioxide, and water vapor. Invariably, the nitrogen from the air was a little denser than the nitrogen from ammonia. Lord Rayleigh’s work caught the attention of Sir William Ramsay, a professor of chemistry at the University College London. In 1898 Ramsay passed nitrogen, which he had obtained by Rayleigh’s procedure over hot magnesium to turn it into magnesium nitride.

After all of the nitrogen had reacted with magnesium, Ramsay was left with unknown gas would couldn’t combine with anything. With the help of Sir William Crookes, Ramsay and Lord Rayleigh found that the emission of spectrum of the gas did not match any of the known elements. They came to conclude that is was a new type of element. They determined its atomic mass to be 39.95amu and called it argon. With this new argon found, other noble gasses were quick to be discovered. Also in 1898 Ramsay isolated helium from uranium ore. From the atomic masses of helium and argon, their lack of chemical reactivity and what was known about the periodic table, Ramsay was convinced that there were other unreactive gasses and that they were all member of one unreactive group. He and his student, Morris Travers set out to find the unknown gasses. They used a refrigeration machine called the fractional distillation; they then allowed the liquid air to warm up gradually and collected components that boiled off at different temperature. Into his manner, they analyzed and identified three new elements-neon, krypton and xenon- in only three months. This new three elements in three months were never broken as a record.

Finally, the last member of the noble gases, radon, was discovered by the German chemist Frederick Dorn in 1900. A radioactive element and the heaviest elemental gas known, radon’s discovery not only completed the Group 8A elements, but also advanced our understanding about the nature of radioactive decay and transmutation of elements.

Lord Rayleigh and Ramsay both won Nobel Prizes in1904 for the discovery of Argon. Lord Rayleigh received the prize in physics and Ramsay’s award was in chemistry.