14h 24min, jan 1, 1911 y - Henry Moseley worked with Ernest Rutherford and while analyzing different metals, realized an unrecognized pattern. Moseley’s work led to both the modern definition of atomic number and the recognition that atomic number is the basis for the organization of the periodic table. This conclusion led to Mendeleev’s table to undergo extensive change.
Added to timeline:
Date:
14h 24min, jan 1, 1911 y
Now
~ 115 years ago