Seaborgium is an artificially produced radioactive element with 106 protons–that is, with an atomic number of 106. Scientists have found many isotopes of seaborgium. Different isotopes of an element have the same number of protons but different numbers of neutrons. The most stable isotope of seaborgium has an atomic mass number (total number of protons and neutrons) of 266. This isotope has a half-life of 20 seconds—that is, due to radioactive decay, only half the atoms in a sample of isotope 266 would still be atoms of that isotope after 20 seconds.
The symbol for seaborgium is Sg. Chemists classify seaborgium in the transactinide element group among the transuranium elements . For information on the position of seaborgium on the periodic table, see the article Periodic table .
In 1974, scientists at the Joint Institute for Nuclear Research in Dubna, near Moscow, first announced the production of the element. Dubna was then part of the Soviet Union and is now in Russia. The Soviet scientists had bombarded lead, whose atomic number is 82, with chromium, whose atomic number is 24. Later in 1974, scientists at two California laboratories now known as Lawrence Berkeley National Laboratory and Lawrence Livermore National Laboratory made a rival claim for the discovery of the element. Both groups of scientists had bombarded californium, whose atomic number is 98, with oxygen, which has an atomic number of 8.
In 1986, the International Union of Pure and Applied Chemistry (IUPAC) and the International Union of Pure and Applied Physics formed a working group to review the histories of the elements with atomic numbers from 101 to 109. In 1993, IUPAC accepted the working group’s conclusion that the California laboratories deserved credit for the discovery of the element. Disagreements about what to name the element delayed an official naming until 1997, however. Before being named, seaborgium was commonly referred to as element 106.
Seaborgium is named for American chemist Glenn T. Seaborg , who shared in the discovery of several elements.
