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Atomic Number: 81
Tl
Tl

Thallium

204.3800 u

Category

post-transition metal

State at Room Temperature

solid

Electron Configuration

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p¹

Valence Electrons

3

Lewis Dot:•••

Electronegativity

1.62

Pauling scale

Oxidation States

+1+3

Melting Point

577 K

303.85°C

Boiling Point

1746 K

1472.85°C

Density

11.85

g/cm³

Position in Table

Group 13Period 6p-block

Discovery

Historical Information

Discovered byWilliam Crookes
Year1861

Common Uses

Applications & Industries

Electronics, infrared detectors, cardiac imaging, rat poison

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