All practice pages/Interatomic theory/Elements
Element 103, an actinide
The last of the actinides, named for Ernest Lawrence, inventor of the cyclotron.
Period 7, in the actinide row set below the main table. The other actinides are tinted, and every cell opens its own article.
Lawrencium has 103 electrons, one for every proton, so the atom carries no charge. Below are the same 103 electrons written two ways.
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f¹⁴ 6s² 6p⁶ 6d¹ 7s²
Short form: [Rn] 5f¹⁴ 7s² 7p¹, 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 5f¹⁴ 7p¹, 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.
Lawrencium sits in period 7 and has 7 shells. The period number counts the shells.
The outer shell holds 2 electrons. Those are the ones lawrencium 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 a few atoms at a time in particle accelerators.
Albert Ghiorso, Torbjørn Sikkeland, Almon Larsh and Robert Latimer reported it in 1961 at Berkeley after bombarding californium with boron; work at Dubna followed, and the two laboratories share the credit. It was named after Ernest Lawrence, who invented the cyclotron and founded the Berkeley laboratory.
Research only. Measurements on single atoms in 2015 supported the prediction that its outermost electron sits in a 7p orbital, an effect of relativity on such a heavy atom.
Radioactive; it has only ever existed a few atoms at a time.