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Polonium (Po)

Polonium is a chemical element of the periodic table with chemical symbol Po and atomic number 84 with an atomic weight of 209 u and is classed as post-transition metal and is part of group 16 (oxygen group). Polonium is solid at room temperature.

Polonium in the periodic table

Atomic number84
Group16 (Oxygen group)
ClassificationPost-Transition Metal
Color Silver
Number of protons84 p+
Number of neutrons125 n0
Number of electrons84 e-
From Wikipedia, the free encyclopediaPolonium 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.

Physical properties

Phase at STPSolid
Density9.196 g/cm3
Atomic weight209 u

Thermal properties

Melting point527 K
253.85 °C
488.93 °F
Boiling point1235 K
961.85 °C
1763.33 °F
Heat of vaporization120 kJ/mol

Atomic properties

Electronegativity (Pauling Scale)2
Electron affinity136 kJ/mol
Oxidation states−2, +2, +4, +5, +6
(an amphoteric oxide)
Ionization energies
  1. 812.1 kJ/mol

Electron configuration for polonium

Electron configuration
Shorthand configuration
[Xe] 4f14 5d10 6s2 6p4
Electron configuration
Full configuration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 6s2 6p4
Electron configuration chart
Electrons per shell2, 8, 18, 32, 18, 6
Valence electrons 6
Valency electrons 2,4,6
Bohr model
PoloniumElectron shell for Polonium, created by Injosoft ABPo
Figure: Shell diagram of Polonium (Po) atom.
Orbital Diagram

The history of Polonium

DiscoveryPierre Curie, Marie Curie (1898)
First isolationWilly Marckwald (1902)
Named byPierre Curie, Marie Curie
Discovery of polonium
Tentatively called "radium F", polonium was discovered by Marie and Pierre Curie in July 1898, when it was extracted from the uranium ore pitchblende and identified solely by its strong radioactivity: it was the first element to be so discovered. It was named after Marie Curie's native land of Poland (Latin: Polonia). Poland at the time was under Russian, German, and Austro-Hungarian partition, and did not exist as an independent country. It was Curie's hope that naming the element after her native land would publicize its lack of independence. Polonium may be the first element named to highlight a political controversy. German scientist Willy Marckwald successfully isolated 3 milligrams of polonium in 1902, though at the time he believed it was a new element, which he dubbed "radio-tellurium", and it was not until 1905 that it was demonstrated to be the same as polonium.


List of unique identifiers for Polonium in various chemical registry databases
CAS Number7440-08-6
ChemSpider ID4886482
EC number231-118-2
PubChem CID Number6328143