Four chemical elements have been formally added to the periodic table, completing the scheme’s seventh row. They are the first to be included in the table since 2011, when elements 114 and 116 were added.
The first true iteration of the table was produced in 1869 by the Russian chemist Dmitri Mendeleev. The new additions were formally verified by the International Union of Pure and Applied Chemistry (IUPAC) on 30 December 2015.
The body announced that a team of Russian and American researchers had provided sufficient evidence to claim the discovery of elements 115, 117 and 118. IUPAC awarded credit for the discovery of element 113 to a Japanese team at the Riken Institute.