55 Cs

Caesium

Alkali metal
Atomic number55
CategoryAlkali metal
Atomic mass132.91
Electron configuration[Xe]6s¹
Oxidation states+1
Electronegativity0.79
Melting point28.4 °C
Boiling point671 °C
Density1.93 g/cm³
Crystal structureBody-centred cubic
Group1
Period6
Blocks
Discovered1,860
Crustal abundance3 ppm

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