1. First to propose idea of atom Democritus

2. Wrote out the first four point atomic theory Dalton

3. Found the e - Thomson

4. Experimented with cathode ray tubes Thomson and Goldstein

5. Thomson’s plum pudding

6. Found the electrical charge of the e - Millikan

7. Did the oil drop experiment Millikan

8. Did the gold foil experiment Rutherford

9. Found the proton Goldstein

10. Found the nucleus Rutherford

11. Found the neutron Chadwick

12. Atomic Theory Polka Dalton, Thomson, Rutherford and Bohr. Schrödinger and Heisenberg, and many, many more. Used their brains to venture in the realm of inner space and found the world of the atom was a weird and wondrous place.

13. Dalton did experiments and said, “I think it’s clear, atoms are tiny indestructible spheres.”

14. Thomson worked with cathode rays and said, “I disagree. A plum-pudding model makes much more sense to me.” A new chapter in atomic theory started to unfold.

15. When Rutherford played around with atoms made of gold. When a few of his alpha particles came bounding back, he hypothesized a nucleus had knocked them off the track.

16. Dalton, Thomson, Rutherford and Bohr. Schrödinger and Heisenberg, and many, many more. Used their brains to venture in the realm of inner space and found the world of the atom was a weird and wondrous place.

17. Bohr saw spectral lines for hydrogen and said, “It seems to me.. Electrons move in orbits with specific energies.”

18. Heisenberg said, “Forget it, there’s no way to know the orbit or a path, where the electron’s gonna go.”

19. Schrödinger used lots and lots of fancy mathematics, and made a model of the atom based on quantum mechanics. It has orbitals and those are based on probability. The atom is a fuzzy blob of pure uncertainty.

20. Dalton, Thomson, Rutherford and Bohr. Schrödinger and Heisenberg, and many, many more. Used their brains to venture in the realm of inner space and found the world of the atom was a weird and wondrous place.

21. What do you know about atom?

22. How Atoms Differ Date:

23. Subatomic Particles  PROTONS  p +  In the nucleus  +1 charge  1 amu  ELECTRON  e -  In electron cloud  -1 charge  1 / 1840 amu  NEUTRON  n o  In the nucleus  No charge  1 amu

24. Atomic number  Used to arrange elements in PT by Mosley  # of PROTONS  # of ELECTRONS IF an ATOM

25. Isotopes  Atoms of the same element that differ in the # of neutrons

26. Atomic Mass  The weighted average of all isotopes.  Always a decimal (unless a man-made element)

27. Mass number  Mass of an isotope  Always a whole number – not on PT  # of PROTONS + NEUTRONS

28. Nuclide  Tells atomic # and mass # of an atom 23 11 Na  Sodium-23 has ____ protons, ___ electrons and ____ neutrons

29. Practice

30. 32 16 S

31. 28 14 Si

32. 14 6 C

33. Ions  Atoms with a charge

34. CATIONS  Cations are pawsitive and are written with a plus charge on the upper right.  LOST an e-, have more protons; therefore positive.  Charge indicates the number of electrons lost.  Hint: cation has a t which looks like +

35. ANIONS  Anions are negative and written with a negative charge on the upper right.  GAINED an e-, have more electrons; therefore negative.  Charge indicates number of electrons gained.

36. 36 17 Cl -  _____ protons _____ neutrons _____ electrons

37. Practice

38. 16 8 O -2

39. 108 47 Ag +

40. 80 35 Br -

41. 207 82 Pb +4