Answer:
Arranged the elements on the table in order of increasing number of protons, or atomic number.
Explanation:
Mendeleev listed the known chemical elements in ascending order of atomic mass. However, such classification gave some problems to Mendeleev's table, which was characterized by the impression that some elements appeared to be out of place. An example was argon which, when isolated, did not appear to have the correct mass to justify its position. Its relative atomic mass of 40 is the same as that of calcium, but these differed considerably: while argon is an inert gas, calcium is a very reactive metal.
In the early twentieth century, when Henry Moseley examined the x-ray spectrum of the elements, he found that all atoms of the same chemical element had the same nuclear charge, and therefore had the same number of protons, which consist of the atomic number of the elements. It was quickly concluded that the elements would be in an even more regular pattern when arranged in a table in ascending order of their atomic number rather than atomic mass.
Thus, we can conclude that Moseley revised Mendeleev's periodic table by arranging the elements on the periodic table in ascending order of proton number or atomic number.