โ–ธโ–ธ
  • ๐Ÿ‡ฌ๐Ÿ‡ง Helium
  • ๐Ÿ‡จ๐Ÿ‡ณ ๆฐฆ
  • ๐Ÿ‡ณ๐Ÿ‡ฑ Helium
  • ๐Ÿ‡ซ๐Ÿ‡ท Hélium
  • ๐Ÿ‡ฉ๐Ÿ‡ช Helium
  • ๐Ÿ‡ฎ๐Ÿ‡ฑ ื”ืœื™ื•ื
  • ๐Ÿ‡ฎ๐Ÿ‡น Elio
  • ๐Ÿ‡ฏ๐Ÿ‡ต ใƒ˜ใƒชใ‚ฆใƒ 
  • ๐Ÿ‡ต๐Ÿ‡น Hélio
  • ๐Ÿ‡ท๐Ÿ‡บ ะ“ะตะปะธะน
  • ๐Ÿ‡ช๐Ÿ‡ธ Helio
  • ๐Ÿ‡ธ๐Ÿ‡ช Helium

Helium: the essentials

Helium atoms have 2 electrons and the shell structure is 2. The ground state electronic configuration of neutral helium is 1s2 and the term symbol of helium is 1S0.

Helium: description  

Helium is one of the so-called noble gases. Helium gas is an unreactive, colourless, and odourless monoatomic gas. Helium is available in pressurised tanks.

Helium is the second most abundant element in the universe after hydrogen. α-particles are doubly ionised helium atoms, He2+.

Helium is used in lighter than air balloons and while heavier than hydrogen, is far safer since helium does not burn. Speaking after breathing an atmosphere rich in helium results in a squeaky voice (don't try it!).

Helium is present in the atmosphere at about 0.0005% (1 part in 200000) by volume and is an important component within hydrocarbon gases in the USA. Its origin in these gases is traced to the decay of radioactive elements in rocks.

Emma's first birthday balloon is filled with helium and so rises in air.
Emma's first birthday balloon is filled with helium and so rises in air.

Helium: physical properties

More physical properties...

Helium: heat properties

More thermochemical properties...

Helium: atom sizes

More atomc size properties...

Helium: electronegativities

More electronegativity properties...

Helium: orbital properties

More orbital properties...

Helium: abundances

More geological data...

Helium: crystal structure

He crystal structure
The solid state structure of helium is: bcc (body-centred cubic).

More crystallographic data...

Helium: biological data

Helium has no biological role.

More biological data...

Helium: uses

Uses...

Helium: reactions

Reactions of helium as the element with air, water, halogens, acids, and bases where known.

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Helium: binary compounds

Binary compounds with halogens (known as halides), oxygen (known as oxides), hydrogen (known as hydrides), and other compounds of helium where known.

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Helium: compound properties

Bond strengths; lattice energies of helium halides, hydrides, oxides (where known); and reduction potentials where known.

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Helium: history

Helium was discovered by Sir William Ramsay and independently by N. A. Langley and P. T. Cleve in 1895 at London, England and Uppsala, Sweden. Origin of name: from the Greek word "helios" meaning "sun".

More history...

Helium: isotopes

Isotope abundances of helium
Isotope abundances of helium with the most intense signal set to 100%.

Helium has two isotopes but it consists almost entirely of He-4 with natural He only containing just over 0.0001% of He-3. Thousands of liters of He-3 are used annually in cryogenic applications and He-3 is also used as a neutron counter in nuclear application. He-3 is also applied in magnetic resonance imaging.

More isotope and NMR data...

Helium: isolation

Isolation: there is very little helium on earth as nearly all present during and immediately after the earth's formation has long since been lost as it is so light. Just about all the helium remaining on the planet is the result of radioactive decay. While there is some helium in the atmosphere, currently its isolation from that source by liquefaction and separation of air is not normally economic. This is bacause it is easier, and cheaper, to isolate the gas from certain natural gases. Concentrations of helium in natural gas in the USA are as high as 7% and other good sources include natural gas from some sources in Poland. It is isolable from these gases by liquefaction and separation of from the natural gas. This would not normally be carried out in the laboratory and helium is available commercially in cylinders under pressure.