VIEWPOINT Heaviest Element Has Unusual Shell

T he periodic table continues to evolve, as it has since the publication of the first widely recognized periodic table by Dmitri Mendeleev in 1869. There have been over 700 versions of the table of elements to date [1], with elements regularly being added, filling empty blocks of the table. An example is the late 19th century addition of a new column (group) of elements, the noble gases, by William Ramsay, who received the 1904 Nobel Prize in Chemistry for his discovery [2]. The most recent entry to this column is oganesson (Og), which is the element with the highest known atomic number (Z = 118) [3]. This intriguing new element, which was first synthesized in 2002, completes the seventh row (7p block) of the periodic table and is the first superheavy (Z > 103) noble gas element.