Atomic Number: 81

Name: Thallium

Atomic symbol: Tl

Atomic Weight: 204.383

Electron affinity: -30 kJ/mol

Electron configuration: 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶4d¹⁰5s²5p⁶4f¹⁴5d¹⁰6s²6p¹

Ionization energies: 589 kJ/mol; 1,971 kJ/mol; 2,878 kJ/mol; 4,890 kJ/mol

Pauling electronegativity: 1.8

Melting Point: 304^oC

Boiling Point: 1457^oC

Density: 11.85 g/cm³

Standard potential (volts), M⁺ + e^- ---> M: +0.72

Covalent radius: 1.55 angstroms

Ionic radius: 1.47 angstroms (+1); 1.02 angstroms (+3)

Common oxidation states in compounds: +1, +3