British natural scientist John Dalton transformed the ancient Greek speculative atomic theory into a quantitative chemical theory and proposed the world's first theoretical model of the atom. His theory mainly has the following four points:
① All matter is composed of very tiny, indivisible matter particles, namely atoms.
②The various properties and masses of the atoms of the same element are the same, and the atoms of different elements are mainly manifested in different masses.
③Atoms are tiny, indivisible solid spheres.
④ Atoms are the smallest unit that participates in chemical changes. In chemical reactions, atoms are only rearranged and will not be created or disappeared.
Although it was confirmed by later generations that this was a failed theoretical model, Dalton brought atoms from philosophy to chemistry for the first time, clarifying the direction of future chemists’ efforts, and that chemistry truly evolved from ancient alchemy. After getting rid of it, Dalton was hailed as the "father of modern chemistry" by later generations.