The INTERNET Database of Periodic Tables
|2019 has been designated the International Year of the Periodic Table as it is the 150th Anniversary of the formulation of Mendeleev's Tabelle I|
Discovery of Thorium
Thorium, atomic number 90, has a mass of 232.038 au.
Radioactive element with a very long half-life.
Thorium was first observed or predicted in 1829 by J. Berzelius and first isolated in 1914 by D. Lely, Jr. and L. Hamburger.
|Periodic Table, What is it showing?||
© Mark R. Leach 1999-
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