Most of us who are lucky enough to have had a science education would of course be familiar with the periodic table. Last year (2019) was celebrated as the 150th anniversary of the table, dating from the publications of Mendeleev’s table in 1869. https://en.wikipedia.org/wiki/File:Simple_Periodic_Table_Chart-en.svg There is another chart, not quite so well-known but common, showing the isotopes of each of the elements. https://en.wikipedia.org/wiki/File:Isotopes_and_half-life.svg I have had a background hobby of… Read Article →