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Element 2 - Helium (He) sound

From helios, or sun; discovered in 1868. Almost all the helium in the world comes from natural gas wells in the United States. One well in Arizona produces a gas that is 8 per cent helium. Lighter than air, it is widely used in blimps and balloons in place of highly flammable hydrogen.

Properties

Atomic Number: 2
Atomic Weight: 4.00260
Electron Configuration (at ground state): 1s2
Oxidation States (Bold most stable): 0
Boiling Point (K): 4.216
Melting Point (K): 0.95
Density (at STP -- g/l): 0.1785
Atomic Volume (liquid state at boiling point -- cm3/mol) 31.80
Number of stable isotopes: 2
Covalent Radius (Å): 0.93
First Ionization Potential (V): 24.587
Specific Heat Capacity (at 300K -- J g-1 K-1): 5.193
Heat of Vaporization (kJ/mol): 0.084
Heat of Fusion (kJ/mol): 0.021
Thermal Conductivity (at 300K -- W m-1 K-1): 0.152
Crystal Structure: Hexagonal