PERIODIC TABLE Whiskey Glass

The periodic table, as we know it today, was first arranged by Dmitri Mendeleev in 1869. He organized the elements by increasing atomic weight and grouped them according to similarities in chemical properties, leaving gaps for elements that were not yet discovered. Remarkably, Mendeleev's predictions about the properties and weights of these missing elements, such as gallium and germanium, were proven correct when they were discovered later. This validation of his periodic system not only revolutionized chemistry by providing a systematic framework to understand elements and their interactions but also showcased the predictive power of science.