2019 marks the 150th anniversary of the periodic table as created by Dimitri Mendeleev. He was a Russian chemist who wrote out the then known 63 elements on cards and arranged them in columns and rows according to their chemical and physical properties. To celebrate this anniversary the United Nations has proclaimed 2019 to be the International year of the Periodic Table. General knowledge trivia – Does anyone know – without using google – how many elements there are today?
There were others before Mendeleev who tried to write a periodic table, John Dalton and John Newlands were two such gentlemen. Where Mendeleev was more successful and why his presentation was more accepted was in what he left out of his “table”. Namely he left spaces for elements that had not been discovered. There are many other presentations of the periodic table and the modern table used today is different but the generally accepted founder is Mendeleev.
Further reading of interest can be found here https://iupac.org/united-nations-proclaims-international-year-periodic-table-chemical-elements/
A few stamps to show for your enjoyment. ……and some say philately is boring!
Michael IPDA General Secretary