2. Ions Necessary for bonding.

5. If a neutral atom LOSES electrons the overall charge of the atom is now POSITIVE (+)

6. We call (+) ion = Cation

7. If a neutral atom GAINS electrons then overall charge is negative

8. We call (-) Ion = Anion

9. Anion vs Cation

11. valence electrons are added or removed from a neutral atom.

12. Valence Electrons = Outermost electrons

13. 1)Write down chemical symbol 2)Write the magnitude and charge to the upper right of the symbol (+/-)

14. Why is it a Positive 2?

16. Golden Rule – Octet Rule All elements want to be like the noble gases! (Group 18). They have 8 valence electrons MAGIC NUMBER

18. How do they become like the noble gases They will take the shortest route! (Either gain to get to 8, or lose to get to 0) They may move forward or backwards (again, whichever is easier)

19. Let’s look at Sulfur What ion would sulfur form? Remember, it wants to be like a noble gas (cool kid) and will take the shortest route to be like one of the cool kids

26. Here is where it gets tricky. (OPPOSITE OF COMMON SENSE)

27. 16 Protons - - - - - - - - 16 Electrons But since we GAINED 2 Electrons (which are negative) - - We have 2 electrons left over

28. -2

29. Remember, since we are dealing with electrons, it is the opposite of common sense, if you gain more you become negative, and if you lose more, then you become positive

30. Let’s look at a Bohr Model (of just the valence electrons) of Sulfur 16 Protons 16 Neutrons 6 valence e (look at Previous PT)

31. 16 Protons 16 Neutrons Remember, GAIN to 8, or LOSE to 0 Now has the MAGIC NUMBER 8 Since it gained 2 then it became -2 charged

36. Or Lose 2 (be like Neon)

37. 12 Protons 12 Neutrons Gain to 8, Lose to 0

39. Mg Ion 2 protons left over +2

40. Mg +2

41. Wouldn’t it be nice if there was a simple way to find out the charge of each element EASILY

43. +1 +2 These Vary +3 +/-4 -3-2 0 ION CHARGES

44. Use the bottom periodic table

45. 1 2 These Vary (weirdo) 34567 8 VALENCE ELECTRONS

46. Helium is an exception, only 2 valence electrons

47. Lewis Dot Structure Be How we show valence electrons (w/o) doing a Bohr Model

48. Kr

49. 1s 2 2s 2 2p 6

50. Atoms will lose or gain electrons to meet the octet rule. 8 = stable

51. Sample Problems Sodium - Na 1s 2 2s 2 2p 6 3s 1

52. Cl = Chlorine

54. Oxygen - 1s 2 2s 2 2p 4

55. Magnesium - 1s 2 2s 2 2p 6 3s 2

56. 1)Lithium