Element 117 fits a pattern

The announcement on 7 April of the discovery of element 117 (see the news story on page 11 of this issue) completes row 7 of the periodic table. The discovery of elements 93 and 94 started a 65-year quest to extend the table to higher and higher atomic numbers. Omitting the “trigger” elements 93 and 94, the 24 elements 95-118 have a rather amazing distribution of discovery.

The first six (95-100) were discovered in the US by Albert Ghiorso, Glenn Seaborg, and collaborators. The next six (101-106) were discovered in the US by Ghiorso and collaborators. The next six (107-112) were discovered in Germany by Peter Armbruster and collaborators. The last six (113-118) were discovered in Russia by Yuri Oganessian and collaborators. Although the description is slightly simplified, it is nevertheless significant: US (6), US (6), Germany (6), and Russia (6). The cause of that pattern is easily traceable to the experimental facilities available and the irresistible urge to try just a bit harder to add one more proton. Another amazing fact is that Ghiorso is codiscoverer of 10% of the periodic table. Of course, not every element is as useful as carbon or copper, but who knows? Forever isn’t over yet.