Final answer:
John Dalton started studying atoms to understand why elements combine in fixed ratios, leading to the formulation of Dalton's atomic theory. This theory elucidated that atoms are indivisible and combine in simple ratios, although we now know atoms can be subdivided and can exist as isotopes.
Step-by-step explanation:
The question that led John Dalton to study atoms was essentially concerning why elements combined in certain fixed ratios of weight or volume, particularly evident in gaseous substances. This question stemmed from his observations and the work of his peers, which eventually culminated in his formulation of Dalton's atomic theory. Dalton's ground-breaking inquiry focused on understanding the weights of various elements and compounds, and after noticing that matter always combined in fixed ratios, he proposed that these consistent proportions were due to fundamental, indivisible particles called atoms. Dalton's atomic theory consisted of several postulates:
- Elements are made up of tiny particles called atoms.
- All atoms of a given element are identical; the atoms of different elements have different weights and different chemical properties.
- Atoms cannot be created, divided, or destroyed.
- Atoms of different elements combine in simple, whole-number ratios to form chemical compounds.
- In chemical reactions, atoms are combined, separated, or rearranged.
Despite the robust framework of Dalton's theory, there are parts that are no longer valid. Specifically, with the discovery of subatomic particles, we now know that atoms can indeed be divided into smaller constituents (i.e., protons, neutrons, and electrons), and that not all atoms of an element are identical—this concept eventually led to the discovery of isotopes.