The document traces the evolution of the atomic theory from ancient Greek observations to the modern quantum mechanical model. It describes key discoveries and concepts such as Dalton's atomic theory, Avogadro's hypothesis, the discovery of the electron, Thomson's plum pudding model of the atom, Rutherford's nuclear atom model, and the development of quantum mechanics in the early 20th century which established that atoms and electrons behave as both particles and waves.

1. The Evolution of
the Atomic Theory
By John, Caroline, and Gabi

2. Greek Observations
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3. Discovery ofChemical
Elements
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c.1661

4. Groundbreaking Discoveries on Mass
and Energy
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c. 1774

5. Groundbreaking Discoveries on Mass
and Energy
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1798 - 1806

6. John Dalton (1766-1844)
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1808

7. Dalton’s Atomic Theory

8. First Table of Atomic Masses
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9. Avogadro’s Hypothesis
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1811

10. Interpretations of
Avogadro’s Hypothesis
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11. The Electron
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1898 - 1903

12. Electron Charge
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1909

13. Assumptions from
Thomson’s Theory
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14. The Plum Pudding Model
Negatively charged electrons are
randomly distributed “plums” on the
positive cloud of cake.

15. The Nuclear Atom
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1911

16. The Modern Atom
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17. How to Read an Atomic Symbol
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18. Planck’s Findings:
The Foundations of the Quantum Model
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c. 1900

19. The Photoelectric Effect
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1921

20. The Atomic Spectrum of Hydrogen
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1927

21. The Bohr Model
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1913

22. The Atom’s Quantum
Mechanical Model
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23. Wave Functions
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24. An Overview of the
Quantum Mechanical Model
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1920s