Polonium

Post-transition metal · atomic number 84

84209PoPoloniumSolidPost-transition metal

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.

Properties of Polonium

Element category	Post-transition metal
Atomic number	84
Atomic mass	209 u
Phase at STP	Solid
Group	16
Period	6
Block	p
Electron configuration	[Xe] 4f14 5d10 6s2 6p4
Electrons per shell	2, 8, 18, 32, 18, 6
Electronegativity (Pauling)	2
Melting point	527 K (254 °C)
Boiling point	1235 K (962 °C)
Density	9.196 g/cm3
Discovered by	Pierre Curie

← Bismuth · Periodic table · Astatine → At

About the post-transition metal group

Softer, lower-melting metals beside the transition block — aluminium, tin, lead — abundant in cans, foils, solders and pigments.

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6 elements: Full outer electron shells make these gases almost inert: they barely react, glow in discharge lamps and are used to create unreactive atmospheres.

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9 elements: Softer, lower-melting metals beside the transition block — aluminium, tin, lead — abundant in cans, foils, solders and pigments.

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