ElementsWhat is polonium?
Polonium is a rare, strongly radioactive element found in tiny amounts in uranium ores.
What is polonium used for?
Devices that remove static electricity in industry, and heat sources for some space equipment.
Where the name comes from
From Poland, the home country of Marie Curie, who discovered it with Pierre Curie.
Key facts
- Symbol
- Po
- Atomic number
- 84
- Atomic mass
- 208.98243 u
- Family
- Metalloid
- Period
- 6
- Group
- 16
- Block
- p
- State at room temperature
- Solid
- Melting point
- 253.9 °C (527 K, 489 °F)
- Boiling point
- 961.9 °C (1,235 K, 1,763 °F)
- Density
- 9.32 g/cm³
- Electrons per shell
- 2, 8, 18, 32, 18, 6
- Electron configuration
- [Xe]6s2 4f14 5d10 6p4
- Common oxidation states
- +4, +2
- Electronegativity (Pauling)
- 2
- First ionisation energy
- 8.417 eV
- Electron affinity
- 1.9 eV
- Atomic radius (van der Waals)
- 197 pm
- Discovered
- 1898
Place in the periodic table
Polonium is element number 84. It sits in period 6 (row 6) of the periodic table, in group 16 (column 16), and belongs to the p-block. Just before it comes bismuth (83), and just after it comes astatine (85). In the same column, tellurium is above it and livermorium is below it. Elements in one column tend to behave alike.
Family: Metalloids.
Physical properties
At room temperature polonium is a solid. It melts at 253.9 °C and boils at 961.9 °C, so it stays liquid over a range of 708 degrees. Its density is 9.32 grams per cubic centimetre, so a one-litre block would weigh about 9.32 kilograms. By density it ranks 29th among the 96 elements with a measured value.
Inside the atom
An atom of polonium has 84 protons in its nucleus and, when neutral, 84 electrons around it. The electrons are arranged in 6 shells: 2, 8, 18, 32, 18, 6. The outermost shell holds 6 electrons. Written in full, the electron configuration is [Xe]6s2 4f14 5d10 6p4.
Its electronegativity on the Pauling scale is 2. This number shows how strongly an atom pulls shared electrons towards itself: fluorine, the strongest, is 3.98. Removing one electron from an atom takes 8.417 electronvolts (about 812 kilojoules per mole). One mole of polonium weighs 208.98243 grams, so a single gram contains about 2.88 × 1021 atoms.
The ring picture is a simple model that only counts the electrons in each shell. Real atoms do not look like this.
Next steps
- Work out the weight of a compound that contains polonium with the molar mass calculator.
- Compare it with every other element in the sortable list.
- Test yourself with the symbol quiz.
Figures on this page are from PubChem (U.S. National Library of Medicine), as downloaded on 11 November 2026. See About and data sources.