Top: Science: Chemistry: Elements: Helium


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General Information

Helium comes from the Greek word helios which is the sun. Helium was first detected in 1868. Helium is extracted from natural gas. It has been been used in arc welding, as a cooling agent in a nuclear reactor, and cryogenics. Helium is also used by deep-sea divers by adding it to the oxygen in their air tanks, to counteract the pressure forces on their bodies during deep dives.

Helium is odorless and colorless, and after hydrogen is the most abundant element in the universe. Helium is unique in that it cannot be turned into a solid by lowering the temperature, but only by increasing the pressure.


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Known Isotopes

3He (3.01602931) - 0.000137%
4He (4.00260325) - 99.999863%


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based

1. Taken from http://www.science-park.info/


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Element
Atomic Number: 2
Atomic Mass: 4.002602(2) gmol-1
Melting Point: -272.2°C
Boiling Point: -268.93°C
Standard State: Gas
Density/kgm-3: 0.1785 (0°C)
Atomic Symbol: He

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