Final answer:
The atomic models were developed through experiments such as Rutherford's gold foil experiment, which demonstrated the existence of a small, dense, positively charged nucleus, and Thomson's cathode ray experiment, as well as Millikan's oil drop experiment which helped determine the charge and existence of electrons.
Step-by-step explanation:
Scientists have developed models of the atomic structure through a series of groundbreaking experiments, piecing together our understanding of the atom akin to a jigsaw puzzle. The model of the atomic nucleus, for instance, has formed from the contributions of various scientists over time.
One of the pivotal experiments in atomic theory was conducted by Ernest Rutherford, known as the gold foil experiment. This experiment involved shooting alpha particles at thin gold foil and observing the scattering patterns. Contrary to the then-accepted plum pudding model, which implied that positive charge was evenly spread throughout the atom, Rutherford observed that most particles passed straight through, while a few were deflected at large angles. This led to the revolutionary idea that atoms have a small, dense, positively charged nucleus at their center, with electrons orbiting around this nucleus, thus paving the way for the planetary model of the atom.
Similar to Rutherford's work, the discovery of the electron by J.J. Thomson, via his cathode ray experiments, and Robert Millikan's oil drop experiment, which measured the electron's charge, were also critical for the development of the atomic model. These experiments and many others have provided vital clues to the structure of atoms without direct visualization, contributing to the theoretical models we study today.