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Post-transition metals

Polonium

A rare, intensely radioactive metal discovered by the Curies.

Atomic #84Mass[209]Blockp-blockPeriod6Group16
Po84 · [209]
3D Atom Explorer

Inside the Polonium atom

Switch between Bohr and Quantum Cloud modes to compare a simple teaching model with a more realistic probability-based view, and follow the guided tour to explore the Polonium atom step by step.

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Electron configuration

[Xe] 4f14 5d10 6s2 6p4

A neutral Polonium atom has 84 electrons (equal to its proton count). Choosing a different isotope above changes only the neutron count.

Shell distribution

Shell 12 e⁻Shell 28 e⁻Shell 318 e⁻Shell 432 e⁻Shell 518 e⁻Shell 66 e⁻

Electrons fill inner shells before outer ones; the outermost (valence) shell drives the element's chemistry.

Properties

Physical & atomic properties

State (room temp)
Solid
Melting point
527 K (254 °C)
Boiling point
1235 K (962 °C)
Density
9.32 g/cm³
Electronegativity
2 Pauling
Atomic radius
190 pm
1st ionization energy
812 kJ/mol
Category
Post-transition metals
History

Discovery & naming

Discovered
1898
Discovered by
Marie and Pierre Curie
Origin of name
Poland, Marie Curie's homeland.

Notable uses

Antistatic brushes and compact heat sources.

Cosmic origin

Where Polonium comes from

Neutron star mergers

Occurs on Earth only as a fleeting decay product of uranium and thorium, so it inherits their r-process origin.

Simplified origin map — many elements form through more than one astrophysical pathway.

Summary

Atomic number
84
Atomic mass
[209]
Category
Post-transition metals
Group · Period
16 · 6
Block
p-block
Shells
2 · 8 · 18 · 32 · 18 · 6