Moseley's changes to the periodic table were based mainly on what part of the scientific process?

I believe that the correct answer would be:

“observation of the elements”

Moseley's changes about the periodic table were actually based mainly on observation of the elements. He worked on X-rays which involves the elements. He had arranged the periodic table according to the element's protons without regard to other properties.

explanation:

0.07 g/cm³

1.37 g/cm³