Facts about Noble Gases

The term 'noble gases' is used to refer to the six chemical elements - namely helium, neon, argon, krypton, xenon and radon, which together form Group 18 of the periodic table. Initially, they were also referred to as 'inert gases' as it was believed that they did not react with other elements to form compounds. Of late however, scientists have discovered that quite a few compounds of xenon, krypton and radon can be formed, and therefore the use of term 'inert gases' has been discontinued now. As you move on with this write-up, you will come across more of such interesting facts about noble gases which will make it easier for you to understand the concept.

Discovery of Noble Gases

Noble gases were discovered by Scottish chemist Sir William Ramsay in collaboration with some of the noted names in the field of science like Lord Rayleigh and Morris Travers. The first chemical element of the lot to be discovered was argon which was discovered by Ramsay while working with English physicist Lord Rayleigh in 1894. Eventually, he teamed up with the English chemist Morris Travers and discovered krypton, neon and xenon in 1898. Radioactive radon was added to the list by the German chemist Friedrich Ernst Dorn in 1898. Even though the credit for the discovery of helium goes to the French astronomer Jules Janssen who observed it as a yellow spectral line in the sunlight, it was Sir Ramsay who isolated it for the first time.

Properties of Noble Gases

Basically, noble gases are colorless, odorless, tasteless, and nonflammable gases under standard conditions. In the periodic table, they are arranged in accordance to their boiling point which means you will find helium at the top with the highest boiling point and radon at the bottom with the lowest. Given below is a table which has all the six noble gases enlisted in it which will make it simple for you to understand their properties.

Name	Symbol	Atomic Number	Atomic Weight	Boiling Point	Melting point
Helium	He	2	4	-272.2 °C	-268.93 °C
Neon	Ne	10	20.18	-248.59 °C	-246.08 °C
Argon	Ar	18	39.95	-189.35 °C	-185.85 °C
Krypton	Kr	36	83.8	-157.36 °C	-153.22 °C
Xenon	Xe	54	131.29	-111.7 °C	-108.12 °C
Radon	Rn	86	222	-71.15 °C	-61.85 °C

Even though the noble gases are placed in Group 18 today, they were initially referred to as inert gases, and placed in Group 0 as it was believed that they had a valence of zero which meant it was not possible to form their compounds. Eventually however, studies revealed that these gases had the ability to form compounds, and therefore they were transferred to Group 18 and the use of term inert gases was discontinued. Of the six noble gases, only krypton, xenon, and radon have the ability to form stable compounds which are used as oxidizing agents.

Noble Gases Uses

Owing to these physical and chemical properties of noble gases, they are widely used in different fields - right from incandescent light bulbs to airships. For instance, the buoyancy and in-combustibility of helium makes it an ideal constituent in ultralight aircraft. Similarly, it is also used in diluting oxygen in diving tanks. Being relatively cheap and non-reactive, noble gases are also used to create unreactive environment in various industries. The ability of neon and xenon to absorb and emit electromagnetic radiation makes them important constituents of advertising signs. While orange or red colored advertising signs are produced using neon, blue color in these signs is attributed to the presence of xenon. Similarly, xenon - which is non-inflammable and can be easily eliminated from the body, is used as anesthetic.

That covered some of the most interesting facts about noble gases - some of which you must have heard for the first time. Interestingly, all these noble gases - including helium, are found on the planet. While neon, argon, krypton and xenon are obtained by resorting to liquefaction of gases and fractional distillation, helium is separated from natural gases found on the planet. Radon - on the other hand, is isolated from radioactive decay of radium compounds.