Final answer:
Early atomic theories evolved from the idea of indivisible atoms by the ancient Greeks to the discovery of atoms containing electrons, having a dense central nucleus, and operating in a planetary model as established through crucial experiments by scientists like Dalton, Thomson, and Rutherford.
Step-by-step explanation:
Early Theories of Atomic Structure
The journey to understanding the structure of the atom began with ancient Greek philosophers, who presented the idea that matter consists of small indivisible particles called atoms. However, it wasn't until the 19th century that John Dalton identified that different elements have unique types of atoms, which combine in fixed ratios to form compounds and are conserved during chemical reactions. This paved the way for further exploration into atomic structure.
Experiments conducted later, particularly J.J. Thomson's cathode ray tube experiment, led to the discovery that atoms contain electrons. The quantification of the electron's charge was established through Robert A. Millikan's oil-drop experiments. The revelations continued with Ernest Rutherford's famous gold foil experiment which proposed that atoms have a dense central nucleus, dramatically changing the view on atomic structure. This planetary model suggested that much like planets orbit the sun, electrons orbit a central nucleus.
Rutherford's contribution laid a foundational understanding of the atomic structure, which eventually supported the development of quantum mechanics and the study of sub-atomic particles. These early theories reshaped science and provided the tools necessary for scientists to predict the properties of new materials and further our understanding of chemical and physical phenomena.