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Thallium (Tl) properties


Atomic mass, symbol and atomic number

thallium is a naturally occurring element with the element symbol Tl and the atomic number 81. In the periodic table it stands with an atomic mass of 204.38 u in the 3rd main group. The chemical element discovered by William Crookes in 1861 is not radioactive and is in a solid state at room temperature.

Profile: Thallium (English Thallium)

General
Chemical element:thallium
Symbol:tl
Atomic number:81
Group:boron group
Period:6
Block:p-block
Series:metals
Appearance:silver
explorers:William Crookes
Year of discovery:1861
Atomic properties
Atomic mass:204.38 u
Atomic radius:190 pm
Covalent radius:145 pm
Van der Waals radius:196 pm
Electron configuration:Xe 4f14 5d10 6s2 6p1
ionization:589.4 kJ / mol
Physical Properties
Physical state:firmly
Density:11.85 g / cm3
Crystal structure:hexagonal
Magnetism:diamagnetic
molar volume:17,22 · 10-6 m3/ mol
Mohs hardness:1,2
Melting point:304 ° C
Boiling point:1460 ° C
Heat of fusion:4.2 kJ / mol
Heat of vaporization:162 kJ / mol
Thermal conductivity:46 W
Chemical properties
electronegativity:1,62

Did you know that ...

  • Thallium was formerly used as a rat poison?
  • Thallium has two stable isotopes?
  • Thallium is extremely toxic and can even be absorbed through the skin?