Potassium

Atomic number19
Atomic weight39.0983
Discovery (year)1807
Atomic radius (A)2.26
Melting point (oC)63.5
Boiling point (oC)765.5
Density (g/cm3)0.86
Specific heat (cal/g oC)0.177
Ionization potential (eV)4.341
Electron Affinity (eV)0.5012