In 1808, john dalton proposed a series of statements regarding the atom that became known as dalton's postulates or dalton's atomic theory. since dalton's original proposal, some of the statements have been updated or changed due to new discoveries. which of the statements was not a part of dalton's original atomic theory? matter is comprised of small particles called atoms. all four statements are part of dalton's original atomic theory. different elements have atoms of different masses and properties. atoms of the same element have the same size, mass, and structure. atoms cannot be created or destroyed in a chemical reaction.