Mendeleev’s Periodic Table
In 1869, the Russian chemist, Dmitri Mendeleev published a Periodic Table that forms the basis of the one we use today.
Mendeleev’s Periodic Table was different from those of other scientists in two important ways:
- he arranged the elements in order of increasing atomic weight.
- he left gaps where no element fitted the repeating pattern. These gaps were for undiscovered elements.