Mendeleev鈥檚 periodic table
In 1869, the Russian chemist, Dmitri Mendeleev published a A tabular representation of all known elements in order based on atomic number. that forms the basis of the one we use today.
Mendeleev鈥檚 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.
Mendeleev's periodic table