Boron vs Francium

PropertyB BoronFr Francium
Atomic number587
SymbolBFr
NameBoronFrancium
Categorymetalloidalkali-metal
Standard Atomic Weight10.8135 u223 u
Period27
Group131
Blockps
Phase at STPsolidsolid
Electron configuration[He]2s22p1[Rn]7s1
Oxidation states[-5, -1, 0, 1, 2, 3][1]
Electronegativity (Pauling)2.040.7
Electron affinity0.27972 eV0.491 eV
Density2370 kg/m³1870 kg/m³
Melting point2074.85 °C26.85 °C
Boiling point3999.85 °C-273.15 °C
Discovery year18081939