Four new elements complete the seventh row of the periodic table

Confirmed discoveries of elements 113, 115, 117, and 118 fill the seventh row of the periodic table.

ADAPTED FROM IUPAC BY C. SMITH/SCIENCE

Four new elements complete the seventh row of the periodic table

That periodic table poster on your wall is about to be out of date, thanks to four new chemical elements that just received official recognition. The newcomers are some of the heaviest ever discovered, with atomic numbers of 113, 115, 117, and 118. They will be named by the researchers who identified them, the final step before the elements take up their rightful places in the seventh row of the periodic table.

Chemists classify elements by the number of protons per atom, which they call atomic number. Elements with more than 92 protons are unstable and not normally found in nature, but researchers have worked for decades tosynthesize them and prove their brief existence. The International Union of Pure and Applied Chemistry (IUPAC) assesses the evidence for each new element, deciding when it’s strong enough to warrant official recognition and who should get credit for the discovery. 

Researchers first claimed to have created the heaviest known element, No. 118, in 1999, but the data in that study turned out to be fabricated. The real discoveries of the four new elements came between 2002 and 2010, thanks to a series of experiments with particle accelerators. The particle accelerators fired beams of lighter nuclei at samples of heavy elements, smashing the atoms together until some of them fused. IUPAC credited a team of Russian and U.S. scientists with the discovery of elements 115, 117, and 118. Element 113 will become the first element to be named in Asia, with credit going to a group of Japanese researchers at the RIKEN Nishina Center for Accelerator-Based Science in Wako.

The experiments offered more than a checklist of new elements. By studying how the massive nuclei of the new elements decay, researchers gained insight into the forces that hold atoms together. According to their findings, elements heavier than any yet createdmight have conformations that are especially stable—suggesting that if we can ever make atoms that big, they might stick around for longer than a few microseconds.