Lesson 1.8: History of the Atomic Model скачать в хорошем качестве

Lesson 1.8: History of the Atomic Model

How did scientists figure out what atoms look like—when atoms can’t be seen directly? In this lesson, we trace the development of the atomic model from early philosophical ideas to experimental discoveries that reshaped our understanding of matter. Students will see how each new model was proposed to explain experimental evidence—and why older models had to be revised or replaced. Topics covered include: • Early Greek ideas about matter (Aristotle and Democritus) • Dalton’s atomic theory and evidence from chemical data • Thomson’s discovery of the electron using cathode ray tubes • Rutherford’s gold foil experiment and the nuclear model of the atom • Bohr’s energy-level model based on spectroscopy • Why Bohr’s model works for hydrogen but fails for multi-electron atoms • The emergence of the quantum mechanical model and electron probability clouds This lesson emphasizes an important theme in science: models change as new evidence becomes available. Each atomic model represents a step forward—not because earlier scientists were careless, but because better experiments led to better explanations. Designed for Honors Chemistry with a focus on experimental evidence and scientific reasoning