Helium

He Helium Noble Gas

 

Atomic number:  2 Atomic weight:  4.002602
Shells:  2 Orbitals:  1s2
Melting point:  -272.2°C @ 26 atmos. Boiling point:  -268.934°C
Covalent radius:  0.93 Å Atomic volume:  19.5 cm³/mol
Atomic radius:  0.49 Å Ionic radius:  -- Å
Electronegativity:  0 Oxidation states:  
1st ionization pot.:  24.5874 V 2nd ionization pot.:  54.416 V
3rd ionization pot.:  -- V Specific heat:  5.193 J/gK
Heat of fusion:  -- kJ/mol Heat of vapor.:  0.0845 kJ/mol
Thermal conduct.:  0.00152 W/cmK Electrical conduct.:  -- 10^6/cm ohm
Density:  0.0001787 g/cm³ Valence:  0