PERIODIC ELEMENT
Tl (Thallium)

 



Atomic number : 81
Atomic mass : 204.383 g.mol-1
Electronegativity according to Pauling : 1.8
Density : 11.71 g.cm-3 at 20 °C
Melting point : 304 °C
Boiling point : 1473 °C
Vanderwaals radius : 0.182 nm
Ionic radius : 0.099 nm
Isotopes : 11
Electronic shell : [Xe] 4f14 5d10 6s2 6p1
Energy of first ionisation : 589.1 kJ.mol-1
Energy of second ionisation : 1970 KJ.mol-1
Energy of third ionisation : 2877.4 KJ.mol-1
Discovered by : Sir William Crookes in 1861
 
Atomic Structure Uses (rat and ant poisons, detecting infrared radiation)