Strontium vs Erbium

PropertySr StrontiumEr Erbium
Atomic number3868
SymbolSrEr
NameStrontiumErbium
Categoryalkaline-earth-metallanthanide
Standard Atomic Weight87.62 u167.259 u
Period56
Group2N/A
Blockss
Phase at STPsolidsolid
Electron configuration[Kr]5s2[Xe]6s24f12
Oxidation states[1, 2][0, 1, 2, 3]
Electronegativity (Pauling)0.951.24
Electron affinity0.052 eV0.312 eV
Density2640 kg/m³9070 kg/m³
Melting point776.85 °C1528.85 °C
Boiling point1381.85 °C2867.85 °C
Discovery year17921843