150 years of the periodic table

2019 is proclaimed the “International Year of the Periodic Table” [of Chemical Elements”](IYPT2019).  It is 150 years since Dmitry Mendeleev discovered the periodic system.
The website of the International Union of Pure and Applied Chemistry is well worth a visit – maybe find an activity near you during the year.




Upper image:  2013 (Wikipedia) — middle image: hand drawn in 1961 (Back to Time Warp post)
Below, the very latest 2018 version from the website of the international union of pure and applied chemistry (site gives permission for use).