84PoPolonium209[Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁴
post-transition metal

Polonium

Polonium is a chemical element with symbol Po and atomic number 84, discovered in 1898 by Marie Curie and Pierre Curie. A rare and highly radioactive element with no stable isotopes, polonium is chemically similar to bismuth and tellurium, and it occurs in uranium ores. Applications of polonium are few.

Electronic structure

A stylized shell model. Electrons are quantum objects, not particles following these literal paths. Sizes and motion are illustrative.

Electrons by shell
Electron configuration
4f14
5d10
6s2
6p4

54 is the [Xe] core total across five shells.

Properties

At a glance

Atomic number
84
Atomic mass
209 u
Phase
Solid
Density
9.196 g/cm³
Melting point
527 K
Boiling point
1,235 K
First ionization energy
812.1 kJ/mol
Electronegativity
2
Electron affinity
136 kJ/mol
Molar heat capacity
26.4 J/(mol·K)
Period
6
Appearance
silvery

Conditions and isotopes affect measured properties. Some properties of short-lived elements are predicted. Electronegativity uses the Pauling scale.

Keep exploring

Explore the stories, imagery, and reference data in more depth. Properties with no value in the reference are marked unavailable.