Major Ideas

Dmitri Mendeleev is most noted for creating the first periodic table of the elements. He was the first man to classify all of the known elements in a single table, creating an order of elements based on similar properties. His table grouped elements in order of increasing atomic mass, as opposed to increasing atomic number, the form used commonly today. Catching a pattern in the table he drew, he left spaces empty where he guessed, correctly, elements still to be discovered would be placed. An interesting note: because the noble gases (He, Ne, Ar, Kr, Xe, and Rn) are essentially non-reactive, none of them are present on Mendeleev's table. Mendeleev's biggest accomplishment was most likely that he created a solid basis for future chemists to build off of, which was lacking in his time.