The United Nations has proclaimed 2019 the International Year of the Periodic Table of Chemical Elements (IYPT2019). The same year also marks the 150th anniversary of the publication of Russian chemist Dmitri Mendeleev’s periodic table, containing 63 elements, in which the known elements were arranged horizontally by their atomic weight and vertically in groups of elements with similar "periodic" properties. The present periodic table, containing 118 elements, is completely filled. It includes element 101 named mendelevium (Md). According the United Nations, the purpose of this commemoration of the periodic table is, “to enhance global awareness of and education in the basic sciences.” A number of IYPT2019 special events have been planned. See also: Atomic mass; Mendelevium; Periodic table
