Periodic Table Developments


Alexandre Béguyer de Chancourtois


Alexandre Béguyer de Chancourtois was the first person to create a periodic arrangement of all the known elements, showing that similar elements appear at periodic atom weights. He created the vis tellurique (telluric screw), which is a three-dimensional arrangement of the elements creating an early form of periodic classification.

John Newlands


Newlands is the discoverer of the Periodic Law for the chemical elements. He is remembered for his search for a pattern in inorganic chemistry.
Newlands noticed that there were similarities between elements with atomic weights that differed by seven. He called this The Law of Octaves, drawing a comparison with the octaves of music. There was a periodicity of 7 and not 8 in Newlands table as the nobel gases had not yet been discovered.

Julius Lothar Meyer

1864 - 1870

Julius Lothar Meyer produced many periodic tables. His first consisted of 28 elements, ordered based on their valency. His most famous table was the table that ordered elements according to their atomic weight, with elements of the same valency arranged in vertical lines. He was also the first person to recognise the trends in the properties of of elements and the atomic volume of an element compared to its atomic weight.

Dmitri Mendeleev

1869 - 1896

Mendeleev formed the basis of the periodic table. He ordered the elements based on their atomic weight and realised a pattern in the atomic weight of an element and the properties of those elements. Similar elements were fitted in vertical rows. His table fitted in a new group, the noble gases, which were found after he created his table, perfectly. What was so amazing was that he left gaps for undiscovered elements, and even predicted the properties of them and their compounds

Sir William Ramsay

1892 - 1898

Ramsay discovered the four gases neon, argon, krypton and xenon. He created another family for the elements, the noble gases.

Henry Mosely


Mosely's determined why exceptions to the periodic table (like tellurium and iodine) had to be swapped around in order for the table to be correct, it was because they needed to be sorted according to their atomic number, rather than atomic weight. He found a way to measure the atomic number using an X-ray.