Atomic number = # of protons = # of electrons (neutral atom)

1. INTRO / REVIEW Atomic mass Atomic number = # of protons = # of electrons (neutral atom) Carbon has an atomic number of 6, which means it has 6 ________ in its nucleus and 6 __________ orbiting around the nucleus. protons electrons

2. Organization of Your Periodic Table P E R I O D S GROUPS He, Ne, and Ar are in the same ___________. C, N, and O are in the same ___________.

3. Page 168-169

4. Organization of Your Periodic Table Similar properties: Reactivities Electron Configurations (groups) Families *** Atomic # *** Atomic mass

5. Get out your color coded periodic table!!!

6. Metals Excellent conductors (Sea of electrons) even as solidsMobile electronsMetals are malleable and ductile Can be pulled into wire Can be pounded into sheet

7. Alkali Metals Similar properties: Group # 1 Reactive Good Conductors

8. Alkaline Earth Metals Similar properties: Group # 2 Reactive – but less than alkali Good Conductors

9. noble gases alkali metals halogens alkaline metals transition metals

10. Metals Excellent conductors (Sea of electrons) even as solidsMobile electronsMetals are malleable and ductile Can be pulled into wire Can be pounded into sheet

11. Noble Gases Similar properties: Group # 18 NON-reactive Gases Full outer shells!!!

12. Halogens Similar properties: Group # 17 Very reactive Fluorine and Chlorine = gases 7 valence electrons

13. Transition metals Similar properties: Generally least reactive metals Tricky valence (can change from the expected) Mostly form +1, +2, and +3 ions

14. Can you figure out how reactivity changes on the periodic table?

15. Green = ? Blue = ? Red = ?

17. Inert elements = ? Good Conductors = ?

18. Review • What element is in Group 2, Period 3? • Name an element in Group 3 • How many valence electrons in Xe? • Give me an element with 1 valence electron.

19. Periodic Trends Atomic radius: - Measure of size – radius of an atom - Atoms with more electrons do NOT necessarily have a larger atomic radius

20. Periodic Trends - Atoms with more electrons do NOT necessarily have a larger atomic radius

21. Periodic Trends - Atoms with more electrons do NOT necessarily have a larger atomic radius • Atoms get larger going down a group. • Atoms get smaller going across a period • So why?...

22. Periodic Trends As you move across a period, # of protons increases and outermost energy level stays the same, attractive force between elecs. and pros. pulls the atom tighter (closer to nucleus) - Atoms with more electrons do NOT necessarily have a larger atomic radius

23. Periodic Trends What’s bigger: B or Al B or N N or Zn C or Cl

24. Periodic Trends Ionization energy – energy needed to remove one electron from an atom Li → Li+ + e- … indication of how strongly an atom holds onto its outermost elecs.

25. Periodic Trends The graph on page 178 shows how ionization energies vary with atomic # What element does the black point at (10, 2100) represent? With respect to the periodic table ionization energies show 2 important trends…

26. Periodic Trends With respect to the periodic table ionization energies show 2 important trends… 1. Decrease as you move down a group 2. Increase as you move left to right across a period

27. Periodic Trends How does the ionization energy trend compare to the atomic radius trend? Does this make sense?

28. IN NOTES Periodic Trends What’s bigger: ↑er I. E.: O or C Be or Ca Na or Be Cl of Al Ca or B+3 O Be Be Cl ------

29. IN NOTES Periodic Trends What’s bigger: ↑er I. E.: O or B Mg or Sr K or Be Cl of Si Sr or Al+3 O Mg Be Cl ------

30. Periodic Trends • Successive Ionization energies (removing more than one electron from an atom): • - The 2nd > 1st, the 3rd > 2nd, the 4th > the 3rd • but if you look at the I. E. s there is usually a large jump. Where? PAGE 178

31. Periodic Trends How does atomic radius change? Why? How does ionization energy change? Why?

33. Review Periodic Trends With respect to the periodic table ionization energies show 2 important trends… 1. Decrease as you move down a group 2. Increase as you move left to right across a period

34. Review Periodic Trends How does the ionization energy trend compare to the atomic radius trend? Does this make sense?

35. Review Q of the Day What’s bigger: ↑er I. E.: O or K Mg or Mg+2 S-2 of F-1

36. Review Periodic Trends Octet Rule = ? Octet rule – Atoms tend to gain, lose, or share electrons in order to acquire a full set of valence electrons (8) [2 for H, He, Li, Be, + B]

37. Periodic Trends What is electronegativity? How does it increase on the p. t. ? In this bond: Mg—O, which way do elecs. Shift? WHY? Electronegativity – ability to attract electrons in a bond O, > electroneg.

38. Periodic Trends How does atomic radius change? Why? Bigger down a group and smaller across a period As you move down a group, there are additional energy levels As you move across a period there are additional protons pulling the electron in tighter

39. Periodic Trends How does ion size change? Why? Negative ions get bigger Positive ions get smaller Negative ions gain electrons Positive ions lose electrons

40. Periodic Trends How does ionization energy change? Why? Opposite of size (atomic radius) Electrons are closer to the nucleus and held tighter in smaller atoms

41. Periodic Trends How does reactivity change? Why? Away from the middle Atoms on the outside of the p.t. are closer to achieving the octet rule and so more reactive

42. Periodic Trends How does electronegativity change? Why? Up and to the right (Fr to F) Elements on the right side of the periodic table want electrons to satisfy the octet rule