Helium
Atomic number
2
Atomic weight
4.002602
Discovery (year)
1895
Atomic radius (A)
1.5
Melting point (
o
C)
-272.2
Boiling point (
o
C)
-268.9
Density (g/cm
3
)
0.179
Specific heat (cal/g
o
C)
@
Ionization potential (eV)
24.587
Electron Affinity (eV)
0
