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| Helium
is an "Inert" gas in group VIIIA of the periodic table with atomic number
2, an atomic weight of 4.003. The configuration of the atom is (1s)2,
and it has an atomic radius of 0.208nm. Helium forms an hcp
solid at low temperatures which has a melting point at - 269.7 C and a
density of 0.126. The liquid boils at - 268.9 C. (4.2 K).
The material is an important cryogenic refrigerant. |
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