Helium: Difference between revisions

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|properties=  Inert, colorless, odorless, non-toxic, non-flammable gas
|properties=  Inert, colorless, odorless, non-toxic, non-flammable gas
|compounds=
|compounds=
|uses=Cryogenics, welding, inert purging gas
|uses=Cryogenics, welding, inert purging gas, scientific uses
|hazard=
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'''Helium''' is a [[Chemical elements|chemical element]], having the [[chemical symbol]] He. Its [[atomic number]] (the number of [[proton]]s) is 2. It has a [[Atomic mass#Standard atomic weights of the elements|standard atomic weight]] of 4.002602, and is typically found as a [[gas]] in its elemental form.
'''Helium''' is a [[Chemical elements|chemical element]], typically found as a [[gas]] in its elemental form. It has the [[chemical symbol]] He, [[atomic number]] (number of [[protons]]) ''Z'' = 2, and a [[Atomic mass#Standard atomic weights of the elements|standard atomic weight]] of 4.002602 g/mol.


Helium is considered to be a member of the "[[Noble gas]]" class of element. At a [[pressure]] of 101.325 k[[Pascal (unit)|Pa]], it has a [[boiling point]] of -268.93 °[[Celsius (unit)|C]], and a [[melting point]] of -272.2 °C.
Helium is a monatomic noble gas. At a [[pressure]] of 101.325 k[[Pascal (unit)|Pa]], it has a [[boiling point]] of -268.93 °[[Celsius (unit)|C]], and a [[melting point]] of -272.2 °C.  It is of relatively low density--see [[Benchmark_quantities#Density|Benchmark quantities]].
 
==Isotopes==
The helium atom has two stable [[isotope]]s, <sup>3</sup>H and <sup>4</sup>He.

Revision as of 16:58, 1 January 2021

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Helium
4.002602(2)



  He
2
1s2
[ ? ] Noble gas:
Properties:
Inert, colorless, odorless, non-toxic, non-flammable gas
Uses:
Cryogenics, welding, inert purging gas, scientific uses

Helium is a chemical element, typically found as a gas in its elemental form. It has the chemical symbol He, atomic number (number of protons) Z = 2, and a standard atomic weight of 4.002602 g/mol.

Helium is a monatomic noble gas. At a pressure of 101.325 kPa, it has a boiling point of -268.93 °C, and a melting point of -272.2 °C. It is of relatively low density--see Benchmark quantities.

Isotopes

The helium atom has two stable isotopes, 3H and 4He.