Eternal radiance of inert gases
Noble gases properties and applications
These elements belong to the eighth group of the Periodic Table, and possess stable, full electron shells. Inert gases, or noble gases, are monatomic gases with no color or smell. They glow brightly when current flows through them. They also liquefy and freeze at significantly lower temperatures than other gases. Helium is the lightest among them, followed by neon, argon, krypton, xenon, and radon.
History of discovery
The first inert gas in the periodic system and the first to be discovered was helium. It was observed for the first time by Jules Janssen in 1868 during a total solar eclipse. A quarter of a century later, Lord Rayleigh and William Ramsay isolated a new element they called argon. In 1898, William Ramsay and Morris Travers discovered krypton, xenon, and neon. In 1904, Rayleigh and Ramsay received Nobel Prizes in Physics and Chemistry, respectively, for their discoveries and studies on this topic.
Extraction and chemical properties
Neon, argon, krypton, and xenon are extracted from the air. First, the air is purified of carbon dioxide and moisture and compressed via deep freeze. Next, the liquid air is gradually evaporated by a number of fractional distillations. These four gases are separated during this process using different technical solutions. Helium is obtained via a similar method, but from natural gas. Inert gases are practically chemically inactive due to peculiarities in their electron shell structure: their atoms have full valence electron shells. Valence electrons are an atom’s outer electrons, and are usually the only electrons involved in chemical bonding. However, heavier noble gases, due to the increased distance of the valence electrons from the nucleus, are capable of entering into chemical bonds with strong oxidants such as fluorine and oxygen.
Inert gases have a wide variety of uses. Helium is incorporated in the composition of gas mixtures used in scuba diving and to fill balloons. It can also temporarily affect the pitch of the voice if inhaled. Neon is mainly used to fill aptly-named neon signs and, in liquid form, as a coolant. Argon is used in plasma cutting and some surgical procedures. Krypton is used to fuel SpaceX satellites’ electric propulsion systems and manufacture lasers. Xenon is mainly utilized in IMAX film projection systems and as a contrast agent in CT and MRI scans.