Editing Period 5 element (section)

===Xenon===
{{main|Xenon}}

'''Xenon''' is a [[chemical element]] with the [[chemical symbol|symbol]] '''Xe''' and [[atomic number]] 54. A colorless, heavy, odorless [[noble gas]], xenon occurs in the [[Earth's atmosphere]] in trace amounts.<ref>{{cite encyclopedia
 |author=Staff|year=2007
 |url=http://www.infoplease.com/ce6/sci/A0852881.html
 |title=Xenon|encyclopedia=Columbia Electronic Encyclopedia
 |edition=6th|publisher=Columbia University Press
 |access-date=2007-10-23}}</ref> Although generally unreactive, xenon can undergo a few [[chemical reaction]]s such as the formation of [[xenon hexafluoroplatinate]], the first [[noble gas compound]] to be synthesized.<ref name="lanl">{{cite web
 |author1=Husted, Robert |author2=Boorman, Mollie |date=December 15, 2003
 |url=http://periodic.lanl.gov/54.shtml|title=Xenon
 |publisher=Los Alamos National Laboratory, Chemical Division
 |access-date=2007-09-26
}}</ref><ref>{{cite book
 |last=Rabinovich|first=Viktor Abramovich
 |author2=Vasserman, A. A. |author3=Nedostup, V. I. |author4= Veksler, L. S. |title=Thermophysical properties of neon, argon, krypton, and xenon|year=1988|edition=English-language
 |publisher=Hemisphere Publishing Corp.
 |location=Washington, DC|isbn=0-89116-675-0
 |bibcode=1988wdch...10.....R
 }}—National Standard Reference Data Service of the USSR. Volume 10.</ref><ref name="beautiful">{{cite magazine
 |url=http://www.chem.umn.edu/class/2301/barany03f/fun/beautiful1.pdf
 |title=Chemistry at its Most Beautiful
 |access-date=2007-09-13
 |last=Freemantel
 |first=Michael
 |date=August 25, 2003
 |magazine=Chemical & Engineering News
 |url-status=dead
 |archive-url=https://web.archive.org/web/20160106203608/http://www.chem.umn.edu/class/2301/barany03f/fun/beautiful1.pdf
 |archive-date=January 6, 2016
}}</ref>

Naturally occurring xenon consists of [[Isotopes of xenon|nine stable isotopes]]. There are also over 40 unstable isotopes that undergo [[radioactive decay]]. The isotope ratios of xenon are an important tool for studying the early history of the [[Solar System]].<ref name="kaneoka">{{cite journal
 |last=Kaneoka|first=Ichiro|title=Xenon's Inside Story
 |journal=Science|year=1998|volume=280|issue=5365
 |pages=851–852|doi=10.1126/science.280.5365.851b|s2cid=128502357}}</ref> Radioactive [[xenon-135]] is produced from [[iodine-135]] as a result of [[nuclear fission]], and it acts as the most significant [[neutron absorber]] in [[nuclear reactor]]s.<ref name="stacey">{{cite book
 |first=Weston M.|last=Stacey|year=2007
 |title=Nuclear Reactor Physics|page=213
 |url=https://books.google.com/books?id=y1UgcgVSXSkC&pg=PA213|publisher=Wiley-VCH|isbn=978-3-527-40679-1}}</ref>

Xenon is used in [[xenon flash lamp|flash lamps]]<ref name="burke">{{cite web
 |author=Anonymous|title=History
 |url=http://www.millisecond-cine.com/history.html
 |archive-url=https://web.archive.org/web/20060822141910/http://www.millisecond-cine.com/history.html
 |archive-date=2006-08-22
 |publisher=Millisecond Cinematography
 |access-date=2007-11-07
}}</ref> and [[xenon arc lamp|arc lamps]],<ref name="mellor">{{cite book
 |first=David|last=Mellor|year=2000|page=[https://archive.org/details/soundpersonsguid0000mell/page/186 186]
 |title=Sound Person's Guide to Video
 |publisher=Focal Press
 |isbn=0-240-51595-1|url=https://archive.org/details/soundpersonsguid0000mell|url-access=registration}}</ref> and as a [[general anaesthesia|general anesthetic]].<ref name="Sanders">{{cite journal
 |author1=Sanders, Robert D. |author2=Ma, Daqing |author3=Maze, Mervyn |title=Xenon: elemental anaesthesia in clinical practice
 |journal=British Medical Bulletin
 |year=2005|volume=71|issue=1|pages=115–35
 |doi=10.1093/bmb/ldh034
 |pmid=15728132|doi-access=free}}</ref> The first [[excimer laser]] design used a xenon [[Dimer (chemistry)|dimer]] molecule (Xe<sub>2</sub>) as its [[Active laser medium|lasing medium]],<ref name="basov">{{cite journal
 |doi=10.1070/QE1971v001n01ABEH003011
 |last=Basov|first=N. G.
 |author2=Danilychev, V. A. |author3=Popov, Yu. M.
  |title=Stimulated Emission in the Vacuum Ultraviolet Region
 |journal=Soviet Journal of Quantum Electronics
 |year=1971|volume=1|issue=1|pages=18–22|bibcode = 1971QuEle...1...18B }}</ref> and the earliest [[laser]] designs used xenon flash lamps as [[Laser pumping|pumps]].<ref name="toyserkani">{{cite book
 |last=Toyserkani|first=E.|year=2004
 |author2=Khajepour, A. |author3=Corbin, S. |page=48
 |title=Laser Cladding|publisher=CRC Press
 |isbn=0-8493-2172-7|url=https://books.google.com/books?id=zfvbyCHzVqMC&pg=PA48}}</ref> Xenon is also being used to search for hypothetical [[weakly interacting massive particles]]<ref name="ball">{{cite journal
 |last=Ball|first=Philip|date=May 1, 2002
 |url=http://www.nature.com/news/2002/020429/full/news020429-6.html
 |title=Xenon outs WIMPs|journal=Nature
 |doi=10.1038/news020429-6 |access-date=2007-10-08|url-access=subscription}}</ref> and as the [[propellant]] for [[ion thruster]]s in [[spacecraft]].<ref name="saccoccia">{{cite news
 |last=Saccoccia|first=G. |author2=del Amo, J. G. |author3=Estublier, D.
 |title=Ion engine gets SMART-1 to the Moon
 |date=August 31, 2006|publisher=ESA
 |url=http://www.esa.int/SPECIALS/SMART-1/SEMLZ36LARE_0.html|access-date=2007-10-01}}</ref>