In 1869, Russian scientist Dmitri Mendeleev sketch out a table, putting the elements in columns and rows, ordering them by atomic weight in a way that showed their chemical similarities. To celebrate the anniversary, 2019 has been designated the “International Year of the Periodic Table of Chemical Elements (IYPT2019)” by the United Nations General Assembly and UNESCO. Over the past century and a half, more than a thousand different versions of the periodic table have been created. In the February 2019 issue of Physics World, our columnist Robert P Crease explores why Mendeleev’s system has remained the dominant approach.
