Chemical element · Atomic number 84
Polonium
Polonium in the periodic table: atomic number 84, electron configuration, atomic mass, physical data, oxidation states, media credit and visible sources.
Metalloid
solid
[208.98243] u
Generated illustrationGenerated illustration, Quanta Study. Not a photograph of a sample.
Generated illustration of Polonium; the image does not show a sample of the element.
Highly radioactive element; no freely licensed photograph of a sample is available.
Code-native illustration with the Quanta Study mark inside the image; not a photograph, no AI model involved.
Atomic classification
Shell occupancy
Polonium in the Bohr shell model
This shows the electron distribution of the neutral atom in a simplified shell model.
- K · n=1
- 2 electrons
- L · n=2
- 8 electrons
- M · n=3
- 18 electrons
- N · n=4
- 32 electrons
- O · n=5
- 18 electrons
- P · n=6
- 6 electrons
- Electron configuration
- [Xe]6s2 4f14 5d10 6p4
- Electrons per shell
- 2 · 8 · 18 · 32 · 18 · 6
- Group
- 16
- Period
- 6
- Block
- P
- Element category
- Metalloid
Physical and chemical properties
- Atomic mass
- [208.98243] u
- Standard state
- solid
- Density
- 9.32 g/cm³
- Melting point
- 527 K
- Boiling point
- 1,235 K
- Electronegativity
- 2 (Pauling)
- First ionisation energy
- 8.417 eV
- Oxidation states
- +4, +2
- Discovery
- 1898
Safety and periodic classification
Safety
Safe handling cannot be inferred from Polonium's position in the periodic table alone. Laboratory, classroom and disposal decisions must follow the documentation for the exact material and its safety data sheet.
Position and comparison
Polonium is in period 6, group 16 and the P block. Its direct neighbours by atomic number are Bismuth and Astatine. The recorded Pauling electronegativity is 2. Periodic trends are compared only through the separately sourced neighbouring values.
Sources and scope
PubChem attributes element data to sources including IUPAC, NIST and IAEA. Quanta stores the referenced snapshot locally and leaves unknown values unavailable.
Where Polonium sits among the 118 elements
The table compares the reported values for Polonium with every other element that carries the same value in the snapshot. A rank is not a judgement, it is orientation: it says how unusual this value is across the periodic table.
| Value | Polonium | Position in the data set |
|---|---|---|
| Melting point | 527 K | Rank 77 of 103 elements with a reported value. Highest: Carbon. |
| Boiling point | 1,235 K | Rank 69 of 93 elements with a reported value. Highest: Rhenium. |
| Density | 9.32 g/cm³ | Rank 30 of 96 elements with a reported value. Highest: Osmium. |
| Electronegativity (Pauling) | 2 | Rank 32 of 95 elements with a reported value. Highest: Fluorine. |
| Ionisation energy | 8.417 eV | Rank 30 of 102 elements with a reported value. Highest: Helium. |
All values and ranks come from the PubChem Periodic Table snapshot, retrieved on 2026-07-15. Elements without a reported value are excluded, so the population differs per row.
The neighbours of Polonium in the periodic table
- Place in the table
- Group 16, period 6, P block. Classified as metalloid, solid at standard conditions.
- Direct neighbours
- Atomic number 84. Preceded by Bismuth, followed by Astatine.
- Same group
- Same number of outer electrons, and therefore similar reactivity to Oxygen, Sulfur, Selenium, Tellurium, Livermorium.
- Discovery
- Recorded in the snapshot as: 1898. Who, where and under what circumstances is not part of that record, so this page carries the sourced year and no discovery narrative.
- Oxidation states
- +4, +2. They follow from the electron configuration [Xe]6s2 4f14 5d10 6p4 and indicate which compounds to expect.
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