An inert gas is any gas that is not reactive under normal circumstances. Unlike the noble gases an inert gas is not necessarily elemental and are often molecular gases. Like the noble gases the tendency for non-reactivity is due to the valence, the outermost electron shell, being complete in all the inert gases. A gas is one of the four main phases of matter (after solid and liquid, and followed by plasma), that subsequently appear as a solid material is subjected to increasingly higher temperatures. ... For the musical band, see Noble Gas (band) The noble gases are the chemical elements in group 18 (old-style Group 0) of the periodic table. ... In science, a molecule is the smallest particle of a pure chemical substance that still retains its chemical composition and properties. ... Valence is a scientific term in chemistry to describe electrons in the outermost orbital. ... In atomic physics, an electron shell, also known as a main energy level, is a group of atomic orbitals with the same value of the principal quantum number n. ...

Although the term "rare gases" is sometimes used as a synonym for the elemental inert gases, i.e. noble gases—they are only rare relative to other gases found in Earth's atmosphere (i.e. air) with the exception of argon which makes up a significant portion of air, around %0.934; hardly rare at all. Because of their unreactivity, and perhaps their relative scarcity, the inert gases were not discovered until helium was discovered to exist in the Sun, where it is abundant, before it was discovered to exist in Earth's atmosphere. This is possible through the analysis of spectral lines. Earth (often referred to as The Earth) is the third planet in the solar system in terms of distance from the Sun, and the fifth in order of size. ... Layers of Atmosphere (NOAA) Air redirects here. ... Look up air in Wiktionary, the free dictionary. ... General Name, Symbol, Number argon, Ar, 18 Chemical series noble gases Group, Period, Block 18, 3, p Appearance colorless Atomic mass 39. ... Look up air in Wiktionary, the free dictionary. ... General Name, Symbol, Number helium, He, 2 Chemical series noble gases Group, Period, Block 18, 1, s Appearance colorless Atomic mass 4. ... The Sun is the star at the center of Earths solar system. ... A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. ...

Helium and neon are the only true elemental inert gases, because they do not form any true chemical compounds, unlike the heavier noble gases (argon, krypton, xenon and radon). General Name, Symbol, Number helium, He, 2 Chemical series noble gases Group, Period, Block 18, 1, s Appearance colorless Atomic mass 4. ... General Name, Symbol, Number neon, Ne, 10 Chemical series noble gases Group, Period, Block 18, 2, p Appearance colorless Atomic mass 20. ... A chemical compound is a chemical substance formed from two or more elements, with a fixed ratio determining the composition. ... The noble gases are a chemical series. ... General Name, Symbol, Number argon, Ar, 18 Chemical series noble gases Group, Period, Block 18, 3, p Appearance colorless Atomic mass 39. ... General Name, Symbol, Number krypton, Kr, 36 Chemical series noble gases Group, Period, Block 18, 4, p Appearance colorless Atomic mass 83. ... General Name, Symbol, Number xenon, Xe, 54 Chemical series noble gases Group, Period, Block 18, 5, p Appearance colorless Atomic mass 131. ... General Name, Symbol, Number radon, Rn, 86 Chemical series noble gases Group, Period, Block 18, 6, p Appearance colorless Atomic mass (222) g/mol Electron configuration [Xe] 4f14 5d10 6s2 6p6 Electrons per shell 2, 8, 18, 32, 18, 8 Physical properties Phase gas Melting point 202 K (-71 °C...

Production

The elemental inert gases are usually obtained by evaporating them off from condensed air at their respective vapor pressures. Evaporation is the process whereby atoms or molecules in a liquid state (or solid state if the substance sublimes) gain sufficient energy to enter the gaseous state. ... Vapor pressure is the pressure of a vapor in equilibrium with its non-vapor phases. ...

Applications

Because of the non-reactive properties of inert gases they are often useful to prevent undesirable chemical reactions from taking place. For example molecular nitrogen, a molecular inert gas, is often used in food packaging to ensure that food does not spoil in transit since no bacteria or fungi can flourish without the reactive gases oxygen or carbon dioxide, which the molecular nitrogen displaces, since most extant cells on Earth require the reactions which these gases are involved in to function. Most importantly since molecular nitrogen is inert it will not cause any reactions to take place in the food, possibly changing the intrinsic taste or smell, nor will it cause any chemical reactions in the human body. Thus the inert gas is used as a passive preservative, preventing biological decay, while being undetectable to the consumer since taste and olfactory senses require a chemical reaction to take place in order to send a signal to the brain. This is in contrast to active preservatives which react with the biological material of bacteria, fungi, and possibly the food itself changing the food's intrinsic taste or smell, or may even act directly on the consumer's taste and olfactory mechanisms. A chemical reaction is a process that results in the interconversion of chemical substances [1]. The substance or substances initially involved in a chemical reaction are called reactants. ... General Name, Symbol, Number nitrogen, N, 7 Chemical series nonmetals Group, Period, Block 15, 2, p Appearance colorless Atomic mass 14. ... Subgroups Actinobacteria Aquificae Bacteroidetes/Chlorobi Chlamydiae/Verrucomicrobia Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Bacteria (singular: bacterium) are a major group of living organisms. ... Divisions Chytridiomycota Zygomycota Ascomycota Basidiomycota The Fungi (singular: fungus) are a large group of organisms ranked as a kingdom within the Domain Eukaryota. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless Atomic mass 15. ... Carbon dioxide is an atmospheric gas comprised of one carbon and two oxygen atoms. ... A chemical reaction is a process that results in the interconversion of chemical substances [1]. The substance or substances initially involved in a chemical reaction are called reactants. ... Human anatomy or anthropotomy is a special field within anatomy. ...

In gas metal arc welding inert gases are used to shield the heated metal from the reactive gases in air which can cause undesirable reactions in the metal. Some gases which are not usually considered inert but which behave like inert gases in all the circumstances likely to be encountered in some use can often be used as a substitute for an inert gas. This is useful when an appropriate pseudo-inert gas can be found which is extrememly cheap and easy to come by. For example carbon dioxide is sometimes used in gas metal arc welding because it is not reactive in the circumstances encountered in arc welding even though it is often reactive in other circumstances. Gas metal arc welding (GMAW), sometimes referred to by its subtypes, metal inert gas (MIG) welding or metal active gas (MAG) welding, is a semi-automatic or automatic arc welding process in which a continuous and consumable wire electrode and a shielding gas are fed through a welding gun. ... Carbon dioxide is an atmospheric gas comprised of one carbon and two oxygen atoms. ... Gas metal arc welding (GMAW), sometimes referred to by its subtypes, metal inert gas (MIG) welding or metal active gas (MAG) welding, is a semi-automatic or automatic arc welding process in which a continuous and consumable wire electrode and a shielding gas are fed through a welding gun. ... Manual Metal Arc welding, also known as stick or MMA welding is one of the most common forms of welding. ...

See also

• inerting system