Look up De Chancourtois.
he is a teacher and he devised the periodic table
He created the first perodic table and organized the element in the periodic table by atomic mass
He found the number of protons an element has. present periodic table is according to it.
JJ Thomson discovered the electron in 1897.
A Periodic table The Periodic Table of the Elements.
he invented the first periodic table..
he is a teacher and he devised the periodic table
In chemistry all most all elements properties are known based on periodic table.
He helped with the periodic table of elemnts.
He created the periodic table.
He found the number of protons an element has. present periodic table is according to it.
He created the first perodic table and organized the element in the periodic table by atomic mass
Julius Lothar Meyer devised a classification of elements into a table that accounted for the periodic variation in properties. his table included 56 elements.
Henry Moseley showed elements in the periodic table should be in order by their atomic number instead of atomic mass.
He created the first periodic table of elements.
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Researching around I would say discovery of the "atomic number" used for ordering the elements in the periodic table would probably be the answer. This is recorded as being in 1913.