Which scientist first arranged elements by atomic number?

In 1869 Russian chemist Dimitri Mendeleev started the development of the periodic table, arranging chemical elements by atomic mass. He predicted the discovery of other elements, and left spaces open in his periodic table for them.

The concept of atomic number evolved from the historic research of Henry Gwyn-Jeffreys Moseley in the 1910s. Moseley bombarded a number of chemical elements with x rays and observed the pattern formed by the reflected rays.

56 moles of   lieter in chemistry