Symbol He Atomic radius: pm - Fusion: kJ/Mole -
Name Helium Ionic radius: pm - Boiling point: C -269
Atomic number 2 Electron affinity Unst Anion Melting point: C -
Atomic weight 4.003 1st  ion potential 24.59 Specific Heat Cap: J/(g K) 5.19
Classification Noble gas Natural form Gas(He2) Thermal Cond: W/(cm K) 0.002
Configuration 1s2 Crystal structure Hex Electrical Cond -
Oxidation states - Density 0.179 Abundance: mg/kg-crust 0.008
Electronegativity - Vaporization: kJ/Mole 0.08    
Helium was discovered in 1895 by Sir William Ramsey. Uses - balloons, blimps, cryogenics, deep sea diving, aluminum welding shield gas (Heliarc)