John Dalton

John Dalton was an english chemist known best for his Atomic Theory. Dalton's Theory consisted of three main points. First off, Dalton stated that each element is composed of extremely small particles, too small to be seen by the naked eye. These particles are called atoms, which Dalton theorized could never be created or destroyed. His second point was that all atoms of the same element are alike in mass and other properties, but the atoms of other elements differ from all other elements. Finally, his third point was that for each compound, different elements combine in a simple numerical ratio. Dalton based his points off the Law of Conservation of Mass and the Law of Constant Composition.
Dalton's second and third points have since been proven incorrect. His first point proven incorrect when scientist split an atom through nuclear fission, and his second was proven incorrect when isotopes were discovered.
Larsen, Delmar. "Atomic Theory." - Chemwiki. N.p., 02 Oct. 2013. Web. 04 Oct. 2015. <http://chemwiki.ucdavis.edu/Physical_Chemistry/Atomic_Theory/Atomic_Theory>.