2. Chapter 3 Atomic Structure 11/6/15 jjs

3. Historical Figures Please refer to your notes taken during project presentations Highlight your notes with information related to these figures

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

5. Lavoisier Conservation of matter Concluded a chemical reaction neither created nor destroyed matter

6. Dalton Atomic theory of matter 4 postulates

7. Dalton’s Postulates 1.Each element is composed of extremely small particles called atoms 2.All atoms of a given element are identical, but they differ from those of any other atoms

8. Dalton’s Postulates 3. Atoms are neither created nor destroyed in chemical reactions 4. A given compound always has the same relative numbers and kinds of atoms

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

10. Accepting Truth by Indirect Evidence How does that work? Can you figure out a problem with indirect evidence? Let’s give it a try… Lab Activity…

11. Indirect Evidence Mass of cup???? Results – Mass of cup? Which method produced the most accurate answer? What are some possible errors? Did errors happen historically with the Atomic Theory?

12. Indirect Evidence (day 2) reporting What were your methods? Group work to present your most accurate method… Explain why it is the most accurate.

13. What is the MASS of the cup?

14. Scanning Tunneling Microscope Atoms in SiliconSilicon

17. Structure Michael Faraday Proved atoms contained particles with a charge

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

19. Charges Positive (+) Negative (-) Like charges repel Opposite charges attract Built up (excess) (-) charge is static electricity When the electrons jump to a … DEMO>>>

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

21. Atomic Structure Review Proton –Positive, 1 amu Neutron –Neutral, 1 amu Electron –Negative, 1/2000 amu

22. The Modern Day Atom Nucleus: –Positively charged protons –Neutral neutrons Orbiting Nucleus: –Negatively charged electrons

23. Atomic Numbers (Z) Equal to number of protons in the nucleus NEVER CHANGES

24. Mass Number (A) Sum of protons and neutrons in the nucleus

25. SymbolNameMassProtonsElectronsNeutronsState at Rm Temp CCarbon12.01666S Mg Magnesium 24.30512 S NeNeon20.17910 G ZnZinc65.40930 35S

26. Isotopes of the Elements Same atomic number but different atomic masses Different number of neutrons

27. Isotopes Defined: –Atoms of the same element with a different number of neutrons. Will have different mass C-12 C-13

28. Average Atomic Mass Ave Mass = (% * mass)+(% * mass) No division needed No division done Only multiplication and addition

29. Ions of the Elements Same number of protons and neutrons Has lost or gained electrons –Contains charge…

30. Practice How many electrons in Na +1 F - Mg +2

31. Pre Lab Questions What is an isotope? Determine the average mass of the following element and abundances. Isotope/mass Abundance Q-54 43% Q-55 29% Q-53 17% Q-56 11% Ave Mass = (% * mass)+(% * mass)

32. Calculations Check your answer 23.22 + 15.95 + 9.01 + 6.16 54.34

33. Vegium LAB Isotope LAB Lab report in Notebook!