The periodic table has finally completed its seventh row, thanks to the scientists in Japan, Russia and the United States for discovering four super-heavy chemical elements: 113, 115, 117 and 118. The new additions are the first since the introduction of elements 114 and 116 to the periodic table in 2011.

The latest additions were formally verified by the International Union of Pure and Applied Chemistry (IUPAC) on Dec. 30, 2015. According to The Economic Times, IUPAC, an organization responsible with selecting the man-made elements seeking a permanent spot on the iconic chart that Russian chemist Dmitri Mendeleev produced in 1869, announced that a team of Japanese, Russian and American researchers had provided sufficient evidence on their discovery of elements 113, 115, 117 and 118.

"The chemistry community is eager to see its most cherished table finally being completed down to the seventh row," IUPAC's Inorganic Chemistry Division President Jan Reedijk said. "IUPAC has now initiated the process of formalizing names and symbols for these elements."

Meanwhile, the new elements are considered as super-heavy elements due to large size of the nuclei of their atoms. To date, element 118 is the heaviest element with 118 protons alongside 176 neutrons. But elements of its size are not routinely found in nature and production in specialized laboratories can take years, Los Angeles Times noted. Super-heavy elements are also highly unstable, existing for just a fraction of a second before they start to decay.

"Probably the only other place where they might exist in a short period of time could be a supernova, where you have so much energy and so many particles that are really heavily concentrated," Lawrence Livermore National Laboratory's Heavy Element Group Principal Investigator Dawn Shaughnessy said. Shaughnessy also had a hand in three of the discoveries.

The newly discovered elements 115, 117 and 118 were created at the Joint Institute for Nuclear Research in Dubna, Russia. Lawrence Livermore scientists and researchers from Oak Ridge National Laboratory in Tennessee and the University of Nevada, Las Vegas worked on all three discoveries. While a consortium of Asian scientists at RIKEN Institute spearheaded by Kosuke Morita discovered element 113.

The teams have also been requested to come up with permanent names and chemical symbols for the now-confirmed elements. The proposed names and symbols will be checked by the Inorganic Chemistry Division of IUPAC for consistency, translatability into other languages and possible prior historic use for other cases.

Until now, the newly-discovered synthetic elements have been known by the generic Latin names ununtrium (Uut or element 113, ununpentium (Uup or element 115), ununseptium (Uus or element 117) and ununoctium (Uuo or element 118). But The Guardian has learned that the new elements can be named after a mythological concept, a mineral, a place or country, a property or a scientist.