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Atomic Number: 91
Pa
Pa

Protactinium

231.0400 u

Category

actinide

State at Room Temperature

solid

Electron Configuration

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 7s² 5f² 6d¹

Valence Electrons

2

Lewis Dot:••

Electronegativity

1.5

Pauling scale

Oxidation States

+5

Melting Point

1841 K

1567.85°C

Boiling Point

4300 K

4026.85°C

Density

15.37

g/cm³

Position in Table

Group Period 7f-block

Discovery

Historical Information

Discovered byKasimir Fajans, Oswald Helmuth Göhring
Year1913

Common Uses

Applications & Industries

Research, dating geological samples

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