Atomic Number (# of protons)

83

Mass (amu)

209.0

Density

9.8 g/cm³ (20⁰C, 1 atm)

Electron Configuration

[Xe]4f¹⁴5d¹⁰6s²p³

Oxidation States (bold = most stable)

+3,+5

Atomic Radius (pm)

155

Ionic Radius (pm)

(+3)103

Electronegativity

1.7

Melting Point (⁰C, 1 atm)

271

Electron Affinity (eV)

0.95

Boiling Point(⁰C, 1 atm)

1564

1^st Ionization energy (eV)

7.29

Enthalpy of Fusion (kJ/mole)

10.9

2^nd Ionization Energy (eV)

Enthalpy of Vaporization (kJ/mole)

151

3^rd Ionization Energy (eV)

Specific Heat Capacity ( J/ (g K), 25⁰C, 1 atm)

0.12