In the early 1800 John Dalton, a meteorologist/ color blindness physician, came up with his own atomic theory and The Dalton Model. Even though, the idea of atoms were already proposed by Democritus, his theory was different in that it had the weight of careful measurements behind it. John Dalton’s Atomic Theory consisted of these facts:
All elements are composed of tiny indivisible particles called atoms.
Atoms of the same elements are identical. The atoms of any one element are different from those of any other element.
Atoms of different elements can physically mix together or can chemically combine with one another in simple whole-number ratios to form compounds
Chemical reactions occur when atoms are separated, joined, or rearranged. Atoms of one element, however, are ever changed into atoms of another element as a result of a chemical reaction.
Important changes were revised from his theory like his atoms are indivisible which is wrong since atoms can be divided into subatomic particles like Protons,Neutrons, and Electrons. Next, is his theory that Atoms of all elements are the same, this is proven wrong by the discovery of isotopes. Lastly, his theory that elements can’t be transformed into other elements, which is also proven wrong