Promethium

Lanthanoid

Only radioactive lanthanoid; no stable isotopes.

Electronic Configuration

[Xe] 4f⁵ 6s²or1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 4f⁵ 6s²

Electron shells

2e⁻

n=1

8e⁻

n=2

18e⁻

n=3

23e⁻

n=4

8e⁻

n=5

2e⁻

n=6

Atomic number

Atomic mass

145 u

Category

Lanthanoid

Block / Group / Period

f · — · 6

Valence electrons

Oxidation states

Electronegativity

1.13

Atomic radius

205 pm

Ionization energy

540 kJ/mol

Electron affinity

50 kJ/mol

Melting point

1315 K / 1042 °C

Boiling point

3273 K / 3000 °C

Density

7.26 g/cm³

State at 25 °C

solid

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