1. Chapter 5
The Periodic Table

2. Objectives Describe how Mendeleev arranged the elements in his table.
Explain how the predictions Mendeleev made and the discovery of new elements demonstrated the usefulness of his periodic table

3. The Meaning of Periodic
Having or marked by repeated cycles.
Happening or appearing at regular intervals.
Recurring or reappearing from time to time; intermittent.

4. Dmitri Mendeleev
1860’s
Only 63 elements were known at that time

5. Mendeleev’s Proposal
Mendeleev arranged the elements into rows in order of increasing mass so that elements with similar properties were in the same column.

6. Periodic Table
An arrangement of elements in columns, based on a set of properties that repeat from row to row.

7. P. 127

8. Mendeleev’s Periodic Table
Not a complete periodic table
Had to leave spaces in his table
Arrange elements by their mass
Placed element with similar properties in the same column
Was able to predict properties of elements yet to be discovered

9. Gallium Mendeleev’s prediction: Soft metal Low melting point
Density of 5.9 g/cm3
Discovery of gallium (1875):
Soft metal
Melting point = 29.7C
Density = 5.91 g/cm3

10. Objectives
Describe the arrangement of elements in the modern periodic table.
Explain how the atomic mass of an element is determined and how atomic mass units are defined.
Identify general properties of metals, nonmetals, and metalloids.

11. The Modern Periodic Table
The elements are arranged by increasing atomic number (number of protons)

12. Period
A row in a periodic table of elements

13. Group A column of elements in a periodic table
Note: Properties of elements repeat in a predictable way when atomic numbers are used to arrange elements into groups.

14. Periodic Law
The pattern of repeating properties displayed by elements in the periodic table

15. Atomic Mass
A value that depends on the distribution of an element’s isotopes in nature and the masses of those isotopes

16. Atomic Mass Unit (amu)
One twelfth (1/12) the mass of a carbon-12 atom

17. Percent found in nature
Chlorine
Isotope
Percent found in nature
Atomic Mass
(AMU)
Chlorine-35
75.78%
34.969
Chlorine-37
24.22%
36.966

18. Classes of Elements
Metals
Nonmetals
Metalloids

19. Metals Elements that are good conductors of heat and electric current
Most metals are malleable and ductile

20. Metals (blue)

21. Transition Metals
Elements that form a bridge between elements on the left and right sides of the periodic table

22. Transition Metals

23. Nonmetals
Elements that are poor conductors of heat and electric current
Note: Many nonmetals have a low melting point which causes them to be gases at room temperature.

24. Nonmetals (yellow)

25. Metalloids
Elements with properties that fall between those of metals and nonmetals
Note: A metalloid’s ability to conduct electric current varies with temperature.

26. Metalloids (pink)

27. Variation Across a Period
From right to left, elements become more metallic and less nonmetallic in their properties

28. Variation Across a Period

29. Objectives
Relate the number of valence electrons to groups in the periodic table and to properties of elements in those groups.
Predict the reactivity of some elements based on their locations within a group.
Identify some properties of common A group elements.

30. Valence Electron

31. Note About Valence Electrons

32. Alkali Metals

33. Alkali Metals

34. Alkaline Earth Metals

35. Alkaline Earth Metals
Magnesium -
Calcium:

36. The Boron Family

37. The Boron Family Metalloid (boron) Metal (aluminum)  Metal (gallium)
Metal (indium)
Metal (thallium)

38. The Boron Family
Aluminum -

39. The Carbon Family

40. The Carbon Family Nonmetal (carbon) Metalloid (silicon)
 Metalloid (germanium)
Metal (tin)
Metal (lead)

41. The Carbon Family
Carbon: -
Silicon:

42. The Nitrogen Family

43. The Nitrogen Family Nonmetal (nitrogen) Nonmetal (phosphorus)
 Metalloid (arsenic)
Metalloid (antimony)
Metal (bismuth)

44. The Nitrogen Family
Nitrogen & Phosphorus: -

45. The Oxygen Family

46. The Oxygen Family Nonmetal (oxygen) Nonmetal (sulfur)
 Nonmetal (selenium)
Metalloid (tellurium)
Metalloid (polonium)

47. The Oxygen Family
Oxygen: -
Sulfur:

48. Halogens

49. Halogens Nonmetal (fluorine) Nonmetal (sulfur)  Nonmetal (bromine)
Nonmetal (iodine)
Metalloid (astatine)

50. Halogens

51. Halogens
Fluorine: -
Chlorine:

52. Noble Gases

53. Noble Gases