![Profile Image](https://pbs.twimg.com/profile_images/1148227150199296001/-U5fmids_normal.jpg)
Russia 🇷🇺 @Russia
📅 #OTD in 1869, brilliant Russian chemist Dmitri #Mendeleev completed the first comprehensive version of the Periodic Table of Chemical Elements. ⚛️ The Table describes elements according to both atomic weigh & valence. Nowadays it includes 118 entries H2O or C2H6O? https://t.co/5HIEay5q7L — PolitiTweet.org