The Nobel Prize in Chemistry 1904 was awarded to Sir William Ramsay "in recognition of his services in the discovery of the inert gaseous elements in air, and his determination of their place in the periodic system".

Lord Rayleigh having proved the remarkable difference in density existing between atmospheric nitrogen and chemically prepared nitrogen, another British scientist, already well-known as an eminent chemist, received permission to co-operate in the continued investigations with the intention of discovering, if possible, the cause of the peculiar state of things previously mentioned. Not content with having proved the presence of argon in the gaseous envelope of the globe, Lord Rayleigh's chemical co-operator, on his own initiative, devoted himself to searching for the occurrence of argon in the solid crust of the earth. As soon as the atomic weight of the two new gases had been approximately determined - as 4 for helium and 40 for argon- the energetic scientist was led, by theoretical reasoning, to search for yet another elementary gas, the atomic weight of which should lie between the two preceding gases and should probably be about 20. It has been demonstrated that the five new gases, or "noble gases" as they are often called, form a natural family of elements which by the absence of electric polarity is strictly differentiated from all elements previously known, filling a void in the periodic system hitherto existing between the highly negative halogens and the highly positive alkali metals.