57La

Lanthanum

Lanthanide

Lanthanum (La) is element 57, a lanthanide, in period 6 and group 3 of the periodic table. Its standard atomic weight is 138.905, it melts at 920 °C and boils at 3464 °C. Discovered by Carl Gustaf Mosander, 1839.

Atomic Number57

SymbolLa

NameLanthanum

Atomic Weight138.905 u

CategoryLanthanide

Period6

Group3

Melting Point920 °C

Boiling Point3464 °C

Density6.145 g/cm³

Electron Config[Xe] 5d1 6s2

Discovered ByCarl Gustaf Mosander, 1839

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