What is Noble gas?
{{See also|Noble gas compound}} The '''noble gases''' are a group of elements that are all [[gas]]es. These elements are all in '''group 18''' of the [[periodic table]]. All of them are [[Monatomic|monoatomic]], meaning each [[molecule]] is a single [[atom]]. They almost never react with other [[chemical element|elements]].<ref>{{cite book |first= Minoru |last= Ozima |author2= Podosek, Frank A. |title= Noble Gas Geochemistry |year= 2002 |publisher= Cambridge University Press |isbn= 0-521-80366-7 |url= https://books.google.com/books?id=CBM2LJDvRtgC |ref= CITEREFOzima2002 }}{{Dead link|date=September 2021 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> This is because they have a full 8 electrons outer electron shell. There are six noble gases: * [[helium]] * [[neon]] * [[argon]] * [[krypton]] * [[xenon]] * [[radon]] All of these gases are found in [[air]]. They make up around 0.96% of the atmosphere. [[Noble gas compound]]s can be formed from noble gases. When the noble gases are used in [[cold cathode]] tubes to produce light, each of them has a different colour. Since [[Radon]] is [[radioactive]], it is usually not used for lighting. Here are pictures of what the others look like: <gallery> Image:HeTube.jpg|Helium Image:NeTube.jpg|Neon Image:ArTube.jpg|Argon Image:KrTube.jpg|Krypton Image:XeTube.jpg|Xenon </gallery> [[Oganesson]] (element 118) is probably the next noble gas after Radon because it is the next box down in the same group. However it has a [[Half-life (element)|half life]] of 0.89 ms, after which it [[decay]]s to [[Livermorium]] (Element 116). This means its use is probably limited. Noble gases were discovered by [[John Strutt|Lord Rayleigh]] and Sir [[William Ramsay]]. Rayleigh won the [[Nobel Prize in Physics]] in 1904 for his work on noble gas.<ref>{{cite web |url= http://www.credoreference.com/entry.do?id=8042959 |title=Rayleigh, John William Strutt, 3rd Baron |first= |last= |work=from Chambers Biographical Dictionary |year=2007|accessdate=30 July 2011}}</ref> Ramsay won the [[Nobel P