All practice pages/Interatomic theory/Elements
Element 97, an actinide
Named for Berkeley, and a rare starting material for making even heavier elements.
Period 7, in the actinide row set below the main table. The other actinides are tinted, and every cell opens its own article.
Berkelium has 97 electrons, one for every proton, so the atom carries no charge. Below are the same 97 electrons written two ways.
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f⁹ 6s² 6p⁶ 7s²
Short form: [Rn] 5f⁹ 7s², where [Rn] stands for the 86 electrons radon already has.
That list runs by shell. In the order the subshells fill it reads [Rn] 7s² 5f⁹, 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.
Berkelium sits in period 7 and has 7 shells. The period number counts the shells.
The outer shell holds 2 electrons. Those are the ones berkelium can lose, gain or share, so they are the ones that decide what it bonds with.
Radioactive, like every actinide. It gives up electrons to form positive ions.
Not found in nature; made in minute amounts in high-flux reactors such as the one at Oak Ridge, Tennessee.
Stanley Thompson, Albert Ghiorso and Glenn Seaborg made it in December 1949 at Berkeley by bombarding americium with alpha particles, and named it after the city.
Research only. In 2009, 22 milligrams of berkelium-249 made at Oak Ridge were flown to Russia and bombarded to make tennessine.
Radioactive, and only ever available in milligram amounts.