Evolution of the periodic table of elements and the chart of nuclides

The elements which exist in the universe, originated predominantly through the nucleo synthesis mechanism at various stages of the stellar evolution - the big bang, the stars, the supernovae and neutron star merger. Some elements also got produced through the nuclear reactions initiated by the cosmic rays with the interstellar matter. In the year 1869, based on the knowledge of nearly 65 elements discovered by that time, the Russian scientist Mendeleev came with the idea of arranging the elements in a systematic manner in the form of a periodic table. While Mendeleev made his table based on the increasing atomic weights of the elements, later on, the table was revised to one based on the increasing atomic number of the elements. Nearly 100 years ago we knew about 92 elements and 300 isotopes of these elements. As a result of intense research, currently we have knowledge of nearly 118 elements and 3500 isotopes. Most of these isotopes are manmade and unstable with half- lives ranging from years to fraction of seconds. The UN has declared the year 2019 as the International Year of the Periodic Table of Chemical Elements, to commemorate the 150 years of the Mendeleev periodic table. An overview of the evolution of the periodic table of elements and the chart of nuclides in the last 150 years will be provided. (author)