1) In the late 1700s, new scientific ideas and improved technology allowed for better understanding of chemistry through experimentation and data collection. Laws of chemistry like conservation of mass and definite proportions were discovered. 2) In 1808, John Dalton developed an atomic theory to explain the laws of chemistry, proposing that all matter is made of tiny indivisible particles called atoms. Atoms of each element are unique and combine in simple whole number ratios to form compounds. 3) Dalton's atomic theory accounted well for the known laws of chemistry and provided a rational scientific explanation for chemical reactions and compositions. While some details were later updated, Dalton's core ideas formed the basis of modern atomic