Protactinium
Atomic number
91
Atomic weight
231.03588
Discovery (year)
1917
Atomic radius (A)
1.6
Melting point (
o
C)
Boiling point (
o
C)
Density (g/cm
3
)
Specific heat (cal/g
o
C)
Ionization potential (eV)
Electron Affinity (eV)
