John Dalton's Contribution To The Atomic Theory

Believed to be the first atomic theorist, the Greek materialist philosopher Democritus explored the nature of stones in 400 B.C. Democritus split a stone in half and concluded that the two halves have the same properties; the only difference between them and the original was size. However, that observation did not hold forever because the more he split the stone pieces into halves, the tougher the process was. At one point, he tried his best but failed to split a small stone piece. He called it "atomos," which is the Greek word for indivisible. The first major observation to atomic theory was thus made: matter is composed of sub-parts which are unvarying and indivisible. He also hypothesized two ideas: different atoms were only different in aspects regarding shape and size, and all atoms are always in motion, resulting in some collisions which cause dissociations or combinations (changes in state of matter).
Around the same time, in the fourth century B.C, an Indian philosopher named Kanada was also working to explain atomic

Dalton linked various laws and ideas to create a relatively accurate atomic theory. The first idea he used in his linking was the Law of Conservation of Mass (formulated by Antoine Lavoisier saying that the total mass of the products equals the total mass of the reactants in a chemical reaction). Lavoisier’s law implied that matter is indestructible, which was crucial to Dalton’s thought formulation. Another important link for Dalton was the Law of Definite Proportions (Joseph Proust proposed it which states that for any quantity of a substance the proportions of the masses of elements composing it will always be tantamount). Dalton reworded this law and took a step further, stating that elements combine in integer ratios to form compounds. His findings of the most updated atomic model were as