Helium

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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, having the chemical symbol He. Its atomic number (the number of protons) is 2. It has a standard atomic weight of 4.002602 g•mol −1, and is typically found as a gas in its elemental form.

Helium is considered to be a member of the "Noble gas" class of element. At a pressure of 101.325 kPa, it has a boiling point of -268.93 °C, and a melting point of -272.2 °C.