The development of the atomic theory involved the contributions of several scientists over time, and it cannot be attributed to a single individual who "finalized" it. The atomic theory evolved and was refined through the work of multiple scientists from the early 19th century onwards.
One of the key figures in the development of the atomic theory was John Dalton, an English chemist, who proposed his atomic theory in the early 19th century. Dalton's theory stated that elements were composed of indivisible particles called atoms, and that chemical reactions involved the rearrangement of atoms.
However, Dalton's atomic theory was further refined and expanded upon by subsequent scientists. For instance, J.J. Thomson discovered the electron in 1897, providing evidence that atoms were not indivisible as previously thought, but contained subatomic particles. Ernest Rutherford's experiments, particularly the gold foil experiment in 1911, led to the discovery of the atomic nucleus and the concept of a mostly empty space within an atom.
Later contributions from scientists like Niels Bohr, Erwin Schrödinger, and Werner Heisenberg led to the development of quantum mechanics, which provided a more detailed understanding of atomic structure and behavior.
Therefore, the atomic theory was the result of collective contributions and advancements by numerous scientists, and it can be seen as an ongoing process of refinement and expansion rather than being finalized by a single individual.