1. 2-2 Parts of the Atom (Sections 4.6, 4.7) And you!!!

2. Atoms are made of: Protons Neutrons Electrons Location: nucleus nucleus outside nucleus Charge: + neutral or zero -1 Mass: 1 amu (= 1.66 x 10 -24 g) 1 amu ~0 amu (1/1947 amu)

3. Atomic #: the number of protons ; identifies the element !!!!!!!!!!

4. Isotopes atoms of same element (same # of protons) but with different # of neutrons therefore: different masses!!!!!!!!

5. Ions an atom that has gained or lost electron(s), resulting in a net + (positive) or – (negative) charged particles

6. Size atom size in on the order of 1 to 5 angstroms, where an angstrom (A) = 10 -8 cm. 1 A is to 1 cm as 1 cm is to 600 miles! The nucleus is very small and very dense: it’s size is that of a grain of sand to a football field If the nucleus were the size of a pea, it would weight 250 million tons.

7. 2-3 Notation Systems for Protons, Neutrons, and Electrons (Section 4.7)

8. If no number is written for the overall charge, then the charge is assumed to be zero; that is, there are equal number of protons (+) and electrons (-).

9. Atoms may be either electrically neutral, meaning no charge, positive (+), or negative (-). An atom with a positive or negative charge is called an ion. Ions are formed when atoms gain or lose electrons (remember, electrons have a -1 charge). not by changing the # of protons!!!! If an atom gains 1 electron, it has a -1 charge. If it gains 2 electrons, it has a -2 charge. If an atom loses an electron, it has a +1 charge; loss of 2 e - yields a +2 charge.

10. Practice: #P +, n 0, e - 11 27 +3 14 -3 B Al N 5 13 7 Protons: 5 13 7 Neutrons: 6 14 7 Electrons: 5 10 10

11. A second notation system He – 4 is the same as 4 2 He The atomic number 2 is unique to the element He and doesn’t need to be written!!! No other element has exactly 2 protons, see for yourself!!!

12. More practice: notation, #P +, n o, e - C – 12 C – 13 C – 14 12 6 C 13 6 C 14 6 C #P + : 6 6 6 n O : 6 7 8 e - : 6 6 6

13. Great Job!!!!!!!

14. Difference between Mass # and Atomic weight (avg. atomic mass) Mass # is always a whole number, since it is the sum of the protons + neutrons. The atomic weight is the weighted average of all the element’s isotopes masses; it is a decimal due to the mathematical average. It is what you see on the periodic table! The closest whole number to the atomic mass is the most common isotope of the element. Examples here!

15. Another wonderful practice problem just for you! The natural abundance for boron isotopes is: 19.9% 10 B (10.013 amu) and 80.1% 11 B (11.009amu). Calculate the atomic weight of boron. What did you calculate???

16. You need to take into consideration: The masses of the different isotopes and The prevelence of those isotopes Like this: 10 B: 10 x.199 = 1.99 11 B: 11 x.801 = 8.811 10.801 Therefore: 10.80 = the atomic weight

17. Mass spec demo here

18. 2-4 Mass Spectrometer

19. A Mass Spectrophotometer separates isotopes and gives the relative abundance of each isotope (the %). Electron beam ionizes the atoms and the + cations are accelerated into the magnetic field. The lightest masses are deflected through a greater angle than heavier masses (assuming the atoms all have the same charge). Think about a light car and a heavy truck both taking a curve at a high rate of speed. Who will need to take the wider turn????

20. 2-5 Orbitals (Sections 11.6 – 11.8) Schrӧdinger’s equation allows chemists to describe the probability of locating an electron within a certain region of space around the nucleus. These probability maps are called orbitals, regions of space where there is a 90% probability of locating an electron.

21. Orbital Shapes There are 3 different orbital shapes that we will be interested in: s, p, and d orbitals (an f orbital shape is included below as a link between quantum mechanics and the periodic table). In each box below, draw a picture of the orbital, provide a short description, and indicate the number of orientations on a coordinate axis:

22. s spherical shape z y x One possible orbital orientation therefore: (2 electrons max)

23. p propeller shape z y x Node = region with 0 probability 3 different orbital orientations therefore: ( 6 electrons max)

24. d daisy shape z y x 5 different orbiatal orintations therefore: (10 electrons max)

25. f frustrating to diagram 7 different orbital orientations therefore (14 electrons max)

26. 2-6 electron configurations section 11.9, 11.10 How the orbitals align with the regions of the periodic table s d p f s

27. Please see the orbital filling poster Electrons fill in from the bottom up Take note of levels, sub levels, orbitals One electron per orbital in sublevel first – then pairing up – kind of like college dorms… Use this poster to guide your “orbital notation” diagram

28. Orbital filling poster

29. Electron configurations of the elements Kind of like an address of unexcited electrons Parallel of orbital notation Short hand version useful for elements with many electrons

30. Hydrogen One proton = 1 electron for neutral element Orbital notation: Electron configuration: 1s 1 1s

31. Helium 2 protons = 2 electrons for a neutral element Orbital notation: Electron configuration: 1s 2 1s

32. Lithium 3 protons = 3 electrons for a neutral element Orbital notation: Electron configuration: 1s 2 2s 1 1s 2s

33. Try Berillium on your own Did you find: 4 P+ = 4 e- (for neutral element) Orb. notation: Electron configuration: 1s 2 2s 2 1s 2s

34. Now try Boron please Thank you

35. Boron 5 electrons Orbital notation Electron configuration: 1s 2 2s 2 2p 1 1s2s2p

36. Carbon please Be careful with the filling sequence please

37. Carbon (6e-) 1s2s2p **** Note the filling sequence - one electron per orbital in that sub level prior to pairing up 1s 2 2s 2 2p 2

38. Nitrogen 7e- 1s2s2p **** Note the filling sequence - one electron per orbital in that sub level prior to pairing up 1s 2 2s 2 2p 3

39. Oxygen 8e- 1s2s2p **** Note the filling sequence - one electron per orbital in that sub level prior to pairing up 1s 2 2s 2 2p 4

40. Fluorine 9e- 1s2s2p **** Note the filling sequence - one electron per orbital in that sub level prior to pairing up 1s 2 2s 2 2p 5

41. Neon 10e- 1s2s2p **** Note the filling sequence - one electron per orbital in that sub level prior to pairing up 1s 2 2s 2 2p 6

42. Sodium 11e- 1s2s2p **** Note the filling sequence - one electron per orbital in that sub level prior to pairing up 1s 2 2s 2 2p 6 3s 1 3s

43. Sc 21e- 1s 2s2p 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 1 3s Ar 3p 4s 3d 4s 2 3d 1 Short hand version!!!

44. Zn 30 e- I think you get the orbital diagram thing by now… so we will focus on the electron configuration. 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 Ar 4s 2 3d 10

45. Ga 31 e- 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 1 Ar 4s 2 3d 10 4p 1

46. Pt 78 e- 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 6s 2 4f 14 5d 8 Xe 6s 2 4f 14 5d 8 What really happens!!! Xe 6s 1 4f 14 5d 9 Due to electron promotion We will discuss this more in just a bit

47. Bh 107 e- 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 6s 2 4f 14 5d 10 6p 6 7s 2 5f 14 6d 5 Rn 7s 2 5f 14 6d 5 WOW that was fun!!!!!

48. Exceptions to the Normal Filling Pattern: Some elements (notably Cr, Cu, Mo, Ag in the d block) show “electron promotion”, moving an s electron into one of the d orbitals. Predicted Electron Configuration Actual Electron Configuration Cr:[Ar]4s 2 3d 4 [Ar]4s 1 3d 5 Predicted Orbital Notation Actual Orbital Notation: Cr:[Ar] [Ar] 4s 3d

49. The theory behind “electron promotion” relates to the stability of half-filled orbitals. Why do Mo and Ag show a similar pattern?

50. Using the same reasoning, fill in copper’s configurations below: Predicted Cu e- config. Actual Cu e- config. Predicted Cu orb. Actual Cu orb. (Ar) 4s 2 3d 9 (Ar) 4s 1 3d 10 (Ar) 4s 3d

51. The theory behind “electron promotion” relates to the stability of half-filled orbitals. Why do Mo and Ag show a similar pattern? They have similar orbital filling patterns S 2 d 4 => s 1 d 5 for Mo S 2 d 9 => s 1 d 10 for Ag

52. The real exceptions

54. Electron Dot Structures: A simple, yet effective, picture of the valence electrons (outermost energy level electrons) includes a single dot for each valence electron – only the s and p electrons – not for the d and f electrons!!!!

55. Group 1a # valence e- : e- config.: Second period element dot diagram: 1 s1s1 Li

56. Group 2a # valence e- : e- config.: Second period element dot diagram: 2 s2s2 Be: Notice the parallel to the orbital diagrams!!!!

57. Group 3a # valence e- : e- config.: Second period element dot diagram: 3 s 2 p 1 B:.

58. Group 4a # valence e- : e- config.: Second period element dot diagram: 4 s 2 p 2 C :..

59. Group 5a # valence e- : 5 e- config.: s 2 p 3 Second period element dot diagram: N :...

60. Group 6a # valence e- : 6 e- config.: s 2 p 4 Second period element dot diagram: O :....

61. Group 7a # valence e- : 7 e- config.: s 2 p 5 Second period element dot diagram: F ::...

62. Group 8a # valence e- : 8 e- config.: s 2 p 6 Second period element dot diagram: Ne ::..

63. It is very important to recognize that Only the s and p orbital electrons are the outer most electrons Since these electrons are responsible for the chemistry of the atom These are the only electrons that are used in the orbital diagrams!!!!