jan 1, 1865 - Correlation Between Atomic Mass and Position
Description:
John Newlands (1837-1898) aimed to find patterns in the periodic table. He found similarities between elements with atomic weights that differed by 7. He did not leave gaps for undiscovered elements in his table but he did predict its atomic properties. (He only had a periodicity of 7 since noble gases were not noticed until much later.)Only four years later, Mendeleev would publish a new table with more elements but Newlands would prompt that he actually discovered those elements beforehand.
Added to timeline:
Date:
jan 1, 1865
Now
~ 160 years ago