Created the Electron Cloud Model and found that electrons are in an electron cloud around the nucleus that do not travel in fixed orbits.

Arranged the elements on the periodic table based on atomic mass

Found that electrons travel in fixed orbits around the nucleus

Named the atom based on the greek word meaning indivisible.

Created the Solid Sphere Model and found that elements are atoms with different masses.

Created the Plum Pudding Model and thought that the atom was a positive sphere with negative particles embedded throughout.

Created the Nuclear Model; Gold foil experiment allowed him to discover that the nucleus has a positively charged center with negatively charged electrons.