The element with atomic number 101, Mendeléyevium, is named in honour of the Russian scientist Dmitri Mendeleev - Leaving Cert Chemistry - Question 1(a) - 2015

Dmitri Mendeleev is best known for creating the first widely recognized periodic table of elements. He arranged elements in a table based on increasing atomic mass, which allowed him to highlight the periodicity of elemental properties. This organization revealed that elements exhibit repeating characteristics at regular intervals, thereby establishing a foundational principle of chemical behavior.

Mendeleev's periodic table not only organized known elements but also predicted properties of undiscovered elements. He left gaps in his table where he anticipated new elements would fit and accurately described their expected properties. This predictive capability, along with the systematic arrangement of elements, cemented Mendeleev’s legacy in the field of chemistry.