human
Who developed the periodic table in 1869 and successfully predicted undiscovered elements and their properties?
gpt
Dmitri Mendeleev was a Russian scientist who invented the periodic table in 1869 and was able to predict undiscovered elements and their properties.
Explanation: Dmitri Mendeleev was a Russian chemist who developed the modern periodic table of elements. The periodic table was groundbreaking because it allowed Mendeleev to predict undiscovered elements.