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Promethium
(Pm)
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2
8
18
23
8
2
Animation
Pm
Category
Lanthanoid
Series
lanthanide
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Relative atomic mass
Density
Melting point (°C)
Boiling point (°C)
Electronegativity (Pauling)
—
Half-life
2.62 y
Discovery year
1945
Discovered by
Jacob A. Marinsky
Lawrence E. Glendenin
Charles D. Coryell
Electrons: 61
Protons: 61
Neutrons: 84
Wikipedia
Decay chain
Pm-147
(2.62 y)
β⁻ decay
Sm-147
(1.06×10¹¹ y)
α decay
Nd-143
(stable)
stable
created by @lukaswyss
Promethium (Pm) – Element 61
