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Astronomy Chemical element

Promethium

Promethium (Pm) is a chemical element belonging to the category Inner transition metal (lanthanide), with atomic number 61 and atomic mass 145.0000 u. This sheet describes its fundamental properties, periodic position and physical characteristics.

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Astronomy · Chemical element

Promethium

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Identity

  • Name: Promethium
  • Symbol: Pm
  • Atomic number: 61
  • Atomic mass: 145.0000 u

Position in the periodic table

  • Group: 3
  • Period: 6
  • Category: Inner transition metal (Lanthanide)

Physico-chemical properties

  • Standard state: Solid
  • Melting point: Very high (around 1100°C)
  • Density: Medium (approx. 7.2 g/cm³)
  • Electron configuration: [Xe] 4f⁵ 6s²

Scientific description

Promethium is a chemical element with symbol Pm and atomic number 61. It belongs to the category of inner transition metals (lanthanides) and occupies group 3 and period 6. Its standard atomic mass is approximately 145.0000 u.