As per Dalton’s atomic theory, the atom is the ultimate particle that makes up all matter and it is indivisible. The discovery of subatomic particles (such as protons, neutrons, and electrons) disproved this assumption. This led to the requirement for an atomic model that could account for and explain the stability of all atoms and molecules and could also provide a comparison between the differences in the physical and chemical properties of different elements.
Also, atomic models were quite important in explaining the formation of compounds from two or more atoms. It is important to note that atomic models were also required to explain the emission of electromagnetic radiation by atoms, the origin/source of the radiation, and the characteristics of the electromagnetic radiation.