Thallium

Post-transition metal · 204.383 u · group 13, period 6

Thallium · Tl

Atomic number81

SymbolTl

CategoryPost-transition metal

Standard stateSolid

Group · Period · Block13 · 6 · p

Electron configuration[Xe]6s2 4f14 5d10 6p1

Atomic mass204.383 u

Atomic radius196 pm

Protons / Neutrons / Electrons81 / 123 / 81

Shells (e⁻ per shell)2, 8, 18, 32, 18, 3

Electronegativity (Pauling)1.62

Ionization energy6.108 eV

Electron affinity0.2 eV

Oxidation states+3, +1

Melting point577 K · 303.9 °C

Boiling point1.75e+3 K · 1.47e+3 °C

Density11.8 g/cm³

Year discovered1861

CPK color

#A6544D

State at room temp (25 °C)

solid

Position