Element 81

Thallium (Tl)

81

Tl

thallium

Metal · p block · group 13, period 6

Electron configuration: $[\mathrm{Xe}]\,6s^{2}\,4f^{14}\,5d^{10}\,6p^{1}$
Unpaired electrons: 1 (paramagnetic)
Valence electrons: 3
Molar mass: 204.38 g/mol
Electronegativity: 1.62
Atomic radius: 170 pm
First ionization energy: 589 kJ/mol
Next ionization energies: 1,971, 2,878
Electron affinity: 19 kJ/mol released

Practice

Practice thallium

No course questions are about thallium specifically, but these lessons cover what you need.

Where it comes up in the course