Chapter 6

1. Chapter 6 The Periodic Table

2. Mendeleev’s Periodic Table (3) properties (physical & chemical) of the elements repeat in an orderly way from row to row of the table. Periodicity is the tendency to recur at regular intervals.

3. Quick-write Why isotopes of an element have the same chemical properties?

4. Periodic Table of the Elements

5. The Modern Periodic Table (2) The atomic # = # of p+in the nucleus. Atomic # increases by 1 as you move from element to element across a pd. Each pd (except the 1st ) begins with a metal and ends with a noble gas.

6. Squares in the Periodic Table

7. The Modern Periodic Table (3) • The properties of the elements change in an orderly progression from left to right. • The pattern in properties repeats after group 18 (VIIIA). This regular cycle illustrates periodicity in the properties of the elements.

8. The Periodic Law • Periodic Law • states that the physical and chem properties of the elements repeat in a regular patternwhen they are arranged in order of increasing atomic #.

9. Relationship of the PT to Atomic Structure • Periodic Table • elements are arranged according to atomic # • atomic # tells the # of p+(and e- too) it has.

10. Relationship of the PT to Atomic Structure • The lineup starts with H, which has 1 e-. • He comes next in the 1st pd because He has 2 e-. Li has 3.

11. Relationship of the PT to Atomic Structure • Notice on the PT that Li starts a new period. • Why does the 1st pd have only 2 elements? Only 2 e- can occupy the 1st EL in an atom. The 3rd e- in Li must be at a higher EL.

12. Relationship of the PT to Atomic Structure • Li starts a new period at the far left in the table and becomes the 1st element in a gp. • A group • elements in a vertical column. • Elements have similar chem properties. • Elements in the ‘A’groups have same # valence e-

13. Relationship of the PT to Atomic Structure • Gps are numbered from left to right. ‘A’ groups elements: representative elements ‘B’ group elements: transition elements/transition metals

14. Relationship of the PT to Atomic Structure 1A 8A 2A 3A 4A 5A 6A 7A

15. Atomic Structure of Elements Within a Pd (2) • Every period starts with a gp 1 element (H, Li, Na, K, ...) • has 1 e- at a higher EL than the noble gas of the preceding pd. • has 1 valence e-.

16. Atomic Structure of Elements Within a Pd • Move across a period to the next…, the # of valence e- increases by 1. • Gp 18 elements have the max # of 8 valence e- in their outermost EL.

17. Relationship of the PT to Atomic Structure 1A 8A 2A 3A 4A 5A 6A 7A

18. Atomic Structure of Elements Within a Pd • Gp 18 (VIIIA) elements --- noble gases. • The noble gases, with a full complement of valence e-, are generally unreactive. Octet configuration→moststable e- configuration except He (duplet)

19. Atomic Structure of Elements Within a Pd • The period # (1-7) of an element is the same as the # of its highest EL, • so the valence e- of an element in the 2ndperiod are in the 2nd EL. • A period 3 element such as Al has its valence e- in the 3rd EL.

20. Relationship of the PT to Atomic Structure 1A 8A 2A 3A 4A 5A 6A 7A

21. Atomic Structure of Elements Within a Gp • # of valence e- changes from 1 to 8 from left to right across a pd; • After Gp18, the pattern repeats. • For the main gps (A) elements, the gp # is related to the # of valence e-. • The main gp elements are those in Gps1(1A), 2(A), 13(3A), 14(4A), 15(5A), 16(6A), 17(7A), and 18(8A).

22. Atomic Structure of Elements Within a Gp • For elements in gps1(1A) and 2(2A), 4(4A), the gp # = # valence e-. • For elements in gps13(3A), 14(4A), 15(5A), 16(6A), 17(7A), and 18(8A), the 2nd digit in the gp # is = to the # valence e-.

23. Relationship of the PT to Atomic Structure 1A 8A 2A 3A 4A 5A 6A 7A

24. Atomic Structure of Elements Within a Gp • Because elements in the same gp have the same # of valence e-, → similar chemical properties. • Na is in Gp 1 → 1 valence e-. • Because other elements in gp 1 also have 1 valence e-, → similar chem properties.

25. Atomic Structure of Elements Within a Gp • Cl is in Gp 17 (7A) and has 7 valence e-. • All the other elements in gp 17 also have 7 valence e- → similar chem properties. • Throughout the PT, elements in the same gp have similar chem properties because the have the same # of valence e-.

26. 6.2

27. Atomic Structure of Elements Within a Gp • 5 categories: • alkali metals in Group 1(6; except H), • alkaline earth metals in Group 2 (6), • halogensin Group 17(VIIA), and • noble gases in Group 18(VIIIA) (octet). • transition metals (B groups)

28. Atomic Structure of Elements Within a Gp Because the PT relates gp and pd # to valence e-, it’s useful in predicting atomic structure and, chem properties.

29. Atomic Structure of Elements Within a Gp • e.g. O, in Gp16(6A) and Pd 2, has 6 valence e- (the same as the 2nd digit in the gp #), and these e- are in the 2nd EL (because O is in the 2nd pd). • O has the same # of valence e- as all the other elements in Gp16(6A) → similar chem properties.

30. e- in Energy Levels—Group 16

31. Physical States and Classes of the Elements • close to 80% (≈90) of the elements are metalsoccupying the entire left side (except H) and center . • All metals except Hg exist as solid at ‘usual’ temps • Nonmetals occupy the upper-rt-hand corner. • 18 nonmetals; 11 gases at ‘usual’ temp • Metalloids (7) :located along the boundary between metals and nonmetals.

32. Physical States and Classes of the Elements • Elements are classified as • basis on physical and chemproperties • Metals (alkali, alkaline earth, transition) • metalloids, or • Nonmetals

33. elements metals metalloids

34. Metals • Metals • luster, • conduct heat and electricity • usually bend without breaking • malleable • ductile With the exception of Sn, Pb, and Bi, metals have 1, 2, or 3 valence e-.

35. Metals (2) • All metals except Hgare solids at ‘usual’ temp; • Hg is a liquid at ‘usual’ temperature • most have extremely high m.p. and b.p. • m.p. of Fe : about 1700°C

36. Transition Metals (3) • The elements in Gps3 (3B) thru 12 (2B) → transition elements/metals. • All metals. • Unpredictable chem properties complex atomic structures.

37. Transition Metals (5) • 2 series of elements (58-71 and 90-103) are placed below the main body of the table. • separated from the main table the table very wide. • inner transition elements.

38. Transition Metals (6) • The 1st series (lanthanides) follow element # 57, lanthanum. • 14 elements • rare earth elements (0.01 %). • similar properties.

39. Metals (7) • The 2nd series of inner transition elements, the actinides • radioactive • none beyond U (92) occur in nature.

40. lanthanides and actinides lanthanides and actinides • Unpredictable chem properties • complex atomic structures.

41. Nonmetals (1) Some nonmetals are abundant in nature • The nonmetals O and N make up 99 % of Earth’s atm.

42. Nonmetals (2) C is found in more cpds than all the other elements combined. The many cpds of C, N, and O are important in a wide variety of applications.

43. Nonmetals (3) • nonmetals (most) • don’t conduct electricity and heat • are brittle when solid. • Many are gases (11) at ‘usual’ temp

44. Nonmetals (4) • Their m.p. and b.p. are lower than those of metals. • With the exception of C, nonmetals have 5, 6, 7, or 8 valence e-. • lack the luster of metals.

45. Properties of Metals and Nonmetals

46. Metalloids • Metalloids • have some chemical and physical properties of metals and nonmetals. • lie along the border between metals and nonmetals.

47. Metalloids • Si is probably the most well-known metalloid (computer chips) • six others

48. Metalloids (3) • A semiconductor • is an element that • does not conduct electricity as good as a metal, • but does conduct slightly better than a nonmetal.

49. Semiconductors and Their Uses • TV, computer, handheld electronic games, MP3, cell phones, and calculator are electrical devices

50. Semiconductors and Their Uses • metals generally are good conductors of electricity, • nonmetals are poor conductors, • semiconductors fall in between the 2 extremes.