Polonium (Po)

Polonium properties

Atomic number

84

Atomic mass

209 u

Category

Post-transition metal

Group

16

Period

6

Block

p-block

State at room temp.

Solid

Electronegativity

2

Melting point

527 K (253.9 °C)

Boiling point

1,235 K (961.8 °C)

Density

9.196 g/cm³

Valence electrons

6

Common charges

+2, +4

Oxidation states

+4, +2

Atomic radius

197 pm

Ionization energy

8.417 eV

Electron affinity

1.9 eV

Radioactive

Yes, no stable isotopes

Discovered

1898

Polonium electron configuration

The electron configuration of Polonium (Po) is [Xe] 4f14 5d10 6s2 6p4. Its 84 electrons are arranged in shells as 2, 8, 18, 32, 18, 6.

Protons, neutrons and electrons in Polonium

A neutral Polonium atom has 84 protons and 84 electrons. Most Polonium atoms have about 125 neutrons: the atomic mass rounded to 209, minus the atomic number 84.

Neutrons are approximate: atoms of the same element can have different numbers of neutrons (isotopes). Atomic number and mass

How many valence electrons does Polonium have?

6

Polonium has 6 valence electrons in its outermost shell, shell 6. These are the electrons involved in chemical bonding.

See every element: Periodic table with valence electrons

Polonium orbital diagram

Each box is an orbital that holds up to two electrons with opposite spins (↑↓). The inner shells are the same as the noble gas in brackets. How to write electron configurations

Molar mass of Polonium

209 g/mol

One mole of Polonium atoms (6.022 × 10²³ atoms) has a mass of 209 grams. Use this value to convert between grams and moles.

Polonium facts

• Polonium-210 has a half-life of about 138 days, so a sample loses half its radioactivity in under five months.
• Tobacco plants take up tiny amounts of polonium-210, so smokers inhale traces of it in cigarette smoke.
• Polonium (Po) has atomic number 84 and is a solid at room temperature. It was discovered in 1898.

Position in the periodic table

Polonium is element 84, in period 6 and group 16 of the periodic table, in the p-block.

All post-transition metals

Uses of Polonium

Polonium is so intensely radioactive that it has only a few specialized uses. Small amounts of polonium-210 are used in antistatic devices that remove static charge from film, paper and plastic sheets. Mixed with beryllium it makes a neutron source, and its decay heat was used to keep instruments warm on the Soviet Lunokhod moon rovers.

Who discovered Polonium?

Marie and Pierre Curie discovered polonium in Paris in 1898 while studying the uranium ore pitchblende. Marie Curie named it after her homeland, Poland.

Where does the name come from?

Polonium comes from Polonia, the Latin name for Poland. Marie and Pierre Curie discovered it in 1898 and named it after Marie's homeland, then divided among Russia, Prussia and Austria, to draw attention to its plight.

Discovery timeline