Helium

**Helium** is a chemical element wi seembol **He** an atomic nummer 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heids the noble gas group in the periodic table. Its boilin an meltin pynts are the lawest amang the elements an it exists anly as a gas except in extreme condeetions.

Helium is the seicont lichtest element an is the seicont maist abundant element in the observable universe, bein present at aboot 24% o the tot elemental mass, which is mair nor 12 times the mass o aw the hivier elements combined. Its abundance is seemilar tae this figure in the Sun an in Jupiter. This is due tae the very heich nuclear bindin energy (per nucleon) o helium-4 wi respect tae the next three elements efter helium. This helium-4 bindin energy an aa accoonts for why it is a product o baith nuclear fusion an radioactive decay. Maist helium in the universe is helium-4, an is believed tae hae been fairmed durin the Big Bang. Lairge amoonts o new helium are bein creatit bi nuclear fusion o hydrogen in starns.

Helium is named for the Greek God o the Sun, Helios. It wis first detectit as an unkent yellae spectral line signatur in sunlicht durin a solar eclipse in 1868 bi French astronomer Jules Janssen. Janssen is jyntly creditit wi detectin the element alang wi Norman Lockyer. Jannsen observed durin the solar eclipse o 1868 while Lockyer observed frae Breetain. Lockyer wis the first tae propose that the line wis due tae a new element, which he named. The formal discovery o the element wis made in 1895 bi twa Swadish chemists, Per Teodor Cleve an Nils Abraham Langlet, who foond helium emanatin frae the uranium ore cleveite. In 1903, muckle reserves o helium wur foond in naitural gas fields in pairts o the Unitit States, which is bi far the mucklest supplier o the gas the day.

Helium is uised in cryogenics (its mucklest single uise, absorbin aboot a quarter o production), parteecularly in the cuilin o superconductin magnets, wi the main commercial application bein in MRI scanners. Helium's ither industrial uises—as a pressurizin an purge gas, as a protective atmosphere for arc waldin an in processes sic as growin crystals tae mak silicon wafers—accoont for hauf o the gas produced. A well-kent but minor uise is as a liftin gas in balloons an airships. As wi ony gas wi differin density frae air, inhalin a smaa volume o helium temporarily chynges the timbre an quality o the human vyce. In scienteefic research, the behaviour o the twa fluid phases o helium-4 (helium&nbsp;I an helium&nbsp;II), is important tae researchers studyin quantum mechanics (in parteecular the property o superfluidity) an tae those leukin at the phenomena, sic as superconductivity, that temperaturs near absolute zero produce in matter.

On Yird it is relatively rare—0.00052% bi volume in the atmosphere. Maist terrestrial helium present the day is creatit bi the naitural radioactive decay o hivy radioactive elements (thorium an uranium, awtho thare are ither examples), as the alpha particles emitted bi sic decays conseest o helium-4 nuclei. This radiogenic helium is trapped wi naitural gas in concentrations up tae 7% bi volume, frae which it is extractit commercially bi a law-temperatur separation process cried fractional distillation.

## References

## Freemit airtins
;General
* U.S. Govrenment's Bureau o Land Management: Soorces, Refinement, an Shortage.  Wi some history o helium.
* U.S. Geological Survey publications on helium  beginnin 1996: Helium 
* Whaur is aw the helium?  Aga wabsteid
* It's Elemental&nbsp;– Helium 
* Chemistry in its element podcast (MP3) frae the Ryal Society o Chemistry's Chemistry Warld: Helium
* Internaitional Chemical Safety Cards - Helium; includes heal an safety information regardin accidental exposures tae helium

;Mair detail
* Helium at *[[The Periodic Table o Videos]]* (Varsity o Nottingham)
* Helium  at the Helsinki Varsity o Technology; includes pressur-temperatur phase diagrams for helium-3 an helium-4
* Lancaster Varsity, Ultra Law Temperatur Physics&nbsp;– includes a summary o some law temperatur techniques
;Miscellaneous
* Physics in Speech  wi audio samples that demonstrate the unchynged vyce pitch
* Airticle aboot helium an ither noble gases