All practice pages/Interatomic theory/Elements
Element 84, a post-transition metal
The first element Marie Curie discovered, named for her homeland, and one of the deadliest substances known.
Period 6, group 16. The other post-transition metals are tinted, and every cell opens its own article.
Polonium has 84 electrons, one for every proton, so the atom carries no charge. Below are the same 84 electrons written two ways.
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 6s² 6p⁴
Short form: [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁴, where [Xe] stands for the 54 electrons xenon already has.
That list runs by shell. In the order the subshells fill it reads [Xe] 6s² 4f¹⁴ 5d¹⁰ 6p⁴, because a subshell fills by its energy, not by its shell number.
The simple form counts electrons shell by shell. The orbital form says which subshell each one sits in: s holds 2, p holds 6, d holds 10 and f holds 14. Shell 4 here is 4s² 4p⁶ 4d¹⁰ 4f¹⁴, and 2 + 6 + 10 + 14 is 32.
Polonium sits in period 6 and has 6 shells. The period number counts the shells.
The outer shell holds 6 electrons. Those are the ones polonium can lose, gain or share, so they are the ones that decide what it bonds with. For a main-group element the group number gives that count: group 16 means 6.
Six valence electrons, like oxygen and sulfur, yet polonium behaves as a metal. Its intense radioactivity heats its own samples and makes its chemistry hard to study.
Uranium ores hold only about 0.1 milligram per ton. Nearly all polonium is made in nuclear reactors by bombarding bismuth-209 with neutrons.
Marie and Pierre Curie found it in 1898 in pitchblende, a uranium ore, months before they found radium. Marie named it after Poland, which was then divided among Russia, Prussia and Austria and did not exist as a country.
Devices that remove static electricity in factories, since its alpha particles make air conduct. It heated Soviet lunar rovers and, mixed with beryllium, served as a neutron source in early nuclear weapons.
Swallowed or inhaled, a few micrograms can kill, because its alpha radiation destroys tissue from inside. Polonium-210 was used to poison Alexander Litvinenko in London in 2006.