It was announced back in December 2015 that four new elements had earned a spot on the periodic table, completing the seventh row. The new elements, with the atomic numbers 113, 115, 117 and 118, all fit the criteria set by the International Union of Pure and Applied Chemistry (IUPAC) for discovery. The atomic number is the total number of protons and neutrons in one atom of the element.
Keeping with tradition, the discoverers from Japan, Russia and the U.S., were informed they could name their elements after a mythological concept or character, a mineral or similar substance, a place, or geographical region, a property of the element, or a scientist. The names of new elements must also retain and reflect historical and chemical consistency, for example, elements in groups 1-16 would have the suffix ‘-ium’.
Before the names of the elements were confirmed last week, their previous monikers were Uut, Uup, Uus, and Uuo in order of increasing atomic number. The new elements with the atomic numbers 113,115,117 and 118 were named nihonium (Nh), moscovium (Mc), tennessine (Ts) and oganesson (Og) respectively. Priority for discovering element 113 was given to Japan, which is exciting news as it will be the first artificial element to be named in East Asia. The team in Japan claimed to have first spotted element 113 in 2004, with a more convincing sighting in 2012.
All four radioactive elements were synthesised in a lab by smashing lighter atomic nuclei. The result is a superheavy element that survives only for a fraction of a second before falling apart into smaller, more stable agglomerations of protons and neutrons. This made the discovery of these elements very difficult.
Although the periodic table is effectively complete, physicists will now try to create element 119 and 120. This may be a feat made possible with current technology, says Rolf-Dietmar Herzberg, a nuclear physicist at the University of Liverpool.