2. Chapter 3 Atomic Structure

3. DEMOCRITUS Greek philosopher 470-380 BC Deduced the ‘atom’ –Greek for Everything in universe is made of

4. Lavoisier Concluded a chemical reaction

5. Proust Law of A given compound always has the same ratios of elements

6. Dalton Atomic theory of matter

7. Dalton’s Postulates Each element is All atoms of a given element are

8. Dalton’s Postulates Atoms are A given compound always

9. How did he know? Indirect evidence Observations on how things reacted

10. Scanning Tunneling Microscope Atoms in SiliconSilicon

13. Structure Michael Faraday Proved atoms contained

14. Ben Franklin Studied static electricity Flew a kite in a thunderstorm Don’t do this at home Concluded 2 charges

15. Charges Positive (+) Negative (-) Like charges Opposite charges Built up When the electrons jump to a door or person…

16. Cathode Rays TV Electrons moving through a glass tube with little pressure inside. J.J. Thompson

17. Atomic Structure Review Proton – Neutron – Electron –

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

19. Atomic Numbers (Z) Equal to NEVER CHANGES

20. Mass Number (A) Sum of

21. Isotopes of the Elements Same Different number of

22. Isotopes Defined: – Will have different mass C-12 C-13

23. Average Atomic Mass Ave Mass = No Only

24. Practice What is the average atomic mass of the following element. Isotope/mass Abundance Q-54 43% Q-55 29% Q-53 17% Q-56 11%

25. Ions of the Elements Same number of Has lost or gained –Contains

26. Practice How many electrons in