2. Chapter 5 Early Atomic Theory and Structure The History of the Atom…

3. Objectives History of Atomic Theory (5.1-5.5, 5.7)History of Atomic Theory (5.1-5.5, 5.7) Subatomic Particles (5.5, 5.8)Subatomic Particles (5.5, 5.8) Atomic Numbers (5.9)Atomic Numbers (5.9) Isotopes (5.10)Isotopes (5.10) Atomic Mass (5.11)Atomic Mass (5.11)

4. Democritus of Abdera ~460 BC to 370 BC World made of Student of Leucippus

5. Democritus of Abdera 1)All matter is composed of 2)There is a void, which is empty space between atoms 3)Atoms are 4)Atoms are 5)Atoms differ in

6. Aristotle Opposed ideas of Democritus Empedoclean theory – Ideas dominate into 17 th century…

7. Atomism in Antiquity Church spoke against atomsChurch spoke against atoms –Did not support God creating earth

8. Atomism in the Middle Ages Artistotle’s works rediscovered (1200s) Catholic ChurchCatholic Church – De Rerum Natura rediscovered in 1417De Rerum Natura rediscovered in 1417 –Prime source for ideas of Leucippus and Democritus

9. Atomism in the Renaissance Dominated by Alchemists – Discovery of many elementsDiscovery of many elements Preparation of mineral acidsPreparation of mineral acids

10. Robert Boyle (1627-1691) Matter is divided into littleMatter is divided into little First to perform truly quantitative experimentsFirst to perform truly quantitative experiments –

11. Antoine Laurent Lavoisier Antoine Laurent Lavoisier Father of Chemistry "It took them only an instant to cut off that head, and a hundred years may not produce another like it."

12. Amadeo Avogadro (1776-1856)

13. John Dalton (1766-1844) Englishman School teacher

14. John Dalton 1.All matter is 2.Atoms of the 3.Atoms cannot

15. John Dalton 4. Atoms of 5. In chemical reactions, atoms are

16. John Dalton Law of Multiple Proportions When two elements form a series of compounds, the ratios of the masses of the second element that combine with 1 gram of the first element can always be reduced to small whole numbers

17. J. J. Thomson 1856-1940 Showed experimentally the existence of

18. J. J. Thomson Cathode Tube Experiment

19. J. J. Thomson

20. Robert A. Millikan Determined charge of an electronDetermined charge of an electron NegativeNegative

21. Ernest Rutherford 1871-1937 Defined

22. Ernest Rutherford

23. The Modern Day Atom Nucleus: – Orbiting Nucleus:

24. Atomic Numbers (Z) Equal to number of

25. Mass Number (A) Sum of

26. Isotopes of the Elements Same atomic number but Different number of

27. Ions of the Elements Same number of Has lost or gained

28. Atomic Mass Measured in atomic mass units –Equal to exactly 1/12 mass of a carbon-12 atom Average relative mass Average atomic mass (seen on periodic table) – – –