Name: Thallium

Atomic Symbol and Mass Number: Tl [81]

Electron Configuration: [Xe] 4f   5d    6s  6p  

Atomic Radii: 170 pm

Electron Affinity: 19.2 kJ mol‑1

Oxidation States  +3 and +1

Electronegativity Value: 1.62

Elemental Group: Post Transition Metal

Uses and Properties:

• Thallium sulfide is used in photocells because its electrical conductivity increases on exposure to infrared light. 

• Thallium oxide is used to make glass that has a high index of refraction. 

• Thallium is also used in gamma radiation detection equipment.

• Thallium is a heavy, bluish-white metal that resembles lead

• Thallium is very soft and melts easily. It is soft enough to cut with an ordinary knife and will leave a mark on paper if rubbed across it.

• Thallium has a melting point of 302°C (576°F) and a boiling point of 1,457°C (2,655°F).

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Lewis Diagram: