"the universe is composed of two elements, the atoms and the void in which they exist and move."
Antoine Lavoisier came up with the Law of Conservation which states that matter cannot be made or destroyed. As well as hinting that matter rearranges but does not disappear.
John Dalton's atomic theory states that an element is one of a kind because all atoms of an element have the same mass.
He worked in thermodynamics and led to the formulations of quantum theory.
Determined the atomic weight of radium to be 225.
Robert Millikan confirmed Thomson's theory by conducting an experiment that he called the oil drop method.
Described the atom as having a central positive nucleus surrounded by negative orbiting electrons.
He used Brownian Motion to accurately calculate the average distance an immersed visible particle would travel in a set time.
Added onto Rutherford's theory with a model that stated that electrons orbit the nucleus in predefined energy levels.
Build on to Bohr's model with the electron cloud model. This gave an understanding of the floating motion of electrons.