Describe the discovery of noble gas?

Noble gas was discovered by a french astronomer Pierre’s Janssen in the year 1868. But before then noble gas was mistakenly isolated by henry cavendish in the year 1785 when he was investigating the compositions of air. Henry cavendish experiment that led to the discovery of noble gas were;

He mixed excess of oxygen with air and subject the mixture to pass through electric spark on the mixture the oxide of nitrogen formed was removed via the dissolution of the mixture in alkali solution and excess of oxygen were also removed when the solution was reacted with potassium sulphate.

After the removal of the two oxides nitrogen and oxygen, cavendish found a read residues of gas left and this residues is neither nitrogen nor oxygen and its formation did not exceed 1/120th component of the original volume of air. What cavendish actually isolated were noble gas but at that time it was not the appropriate time two discovered noble gas because he could not characterized them. But the most interesting story about cavendish isolation is that the figure of the residual gas is remarkably near to the proportions of the atmospheric noble gas as we now known today.

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After cavendish investigation it take almost a century before final discovery of noble gas the discovery come as a result of advanced spectroscopy, periodic classification, and the study of radioactive element.

Discovery of noble gas

the first noble gas to be discovered is the helium. Helium was discovered in a special way on the extraterrestrial before it was found on earth.

Pirre Janssen was a French astronomer who travel to India to study the eclipse of the sun in the year 1868. When Janssen uses his spectroscopy to view the eclipse of the sun he observed a new yellow line near the sodium D line in the sun chromophore spectrum. this new yellow line viewed by Janssen, project to englishman chemist E. Frankland astronomer and Sir J. Norman Lockyer to assume that there is existence of new element which is not yet discovered which is the element helium. Helium which derives its name from Greek word Helios meaning the sun. But Sir William Ramsay establish the terrestrial existence of helium in the year 1895. Ramsay on his experiment show that there is a trace of element present in the uranium mineral, cleveile, and this element has similar spectrum with that of helium.

Helium was discovered in a natural gas by caddy and McFarland in the year 1905 when they were asked to carry out analysis of natural gas sample that will not burn. The most ministry of noble gas chemistry will be traced to Lord Rayleigh based on his 1894 observation.


Rayleigh in order to confirm Prouts hypothesis which say that all element has atomic weight that is multiple that of hydrogen.

Sir Rayleigh carried out accurate measurement of most common gas densities and find out that density of nitrogen obtained from air after removing oxygen and carbon dioxide and water was higher about 0.5% compared to that of nitrogen obtained from ammonia. on his experiment he found out that a litre of nitrogen obtained from air weighed 1.2572g while that of nitrogen obtained from ammonia weighted 1.2506g under the same condition.

When 1.2506g is subtracted from 1.2572g we have 0.0066g left. This little different left project Rayleigh to suspect that an undiscovered element exists in the atmosphere. This did not only portray the exceptional experimental skill of Lord Rayleigh but also include his scientific and the objective style of reasoning and working that pave way for the discovery of the new whole element of the periodic table.

Ramsay continuously treated atmospheric nitrogen with heated magnesium and discovered that little amount of much denser gas often left behind and they will not combine with any other element. And when examine spectroscopically, Lord Rayleigh and Sir W. Ramsay discovered that this rasheed one element show spectral line which we are not observed in any of the previously discovered element.

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Isolations of noble gas argon was announced in the year 1894, argon derive its name from Greek word argor which mean idle or lazy as a result of it in nature. they also discovered that argon could not fit in any of the group of periodic table elements already discovered.

In here 1898 neon was isolated by Sir Williams Ramsay and his assistant Moris W. Travers, neon got it name from Greek word new. the mode of isolation is by fractional distillation of impure liquid of oxygen. in a short while within the same period they discovered another two element krypton and xenon. the element were discovered in a less volatile fractions of liquid air.

Krypton and xenon it name from Greek word which min hidden and xenon which mean stranger

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