Chapter 5: The Periodic Table

1. Chapter 5: The Periodic Table 5.1 Organizing the elements 5.2 The Modern Periodic Table 5.3 Representative groups

2. Section 5.1 Organization of the Elements

3. Search for Order 1750 only 17 elements known 1789 Antoine Lavoisier grouped known elements (4 groups) Metals Non-metals Gases Earths Next 80 yrs scientists looked for better way to classify known elements

4. Mendeleev’s Periodic Table 1869….Dmitri Mendeleev (Russian teacher and chemist) organized known elements while playing solitaire Made deck of cards with elements Listed name, mass and properties Paid attention to how elements reacted in chemical reactions

5. Mendeleev’s Periodic Table Strategy for organization: What did he look at? chemical properties physical properties atomic mass density color melting point Valence electrons (sec 5.3)

6. Mendeleev’s Proposal Elements arranged in rows based on increasing mass. Elements with similar properties are in same column. Chart was a Periodic Table - arrangement of elements in columns based on a set of properties that repeat.

7. Mendeleev’s Prediction Table incomplete– elements not yet discovered Left spaces in table for undiscovered elements Good models allow for predictions to be made based on model Used properties of nearby elements to predict properties of unknown elements

8. He called this element eka-Aluminum. Later it was renamed Gallium after its discovery in 1875

9. Evidence Supporting Mendeleev’s Table • Close match between Mendeleev’s predictions and the actual properties of new elements showed how useful table was. • Ex. Discovery of: Aluminum, Gallium, Scandium, and Germanium http://www.iteachbio.com/Chemistry/Chemistry/The%20Periodic%20Table.mov

10. YOU NEED 3 DIFFERENT COLORED PENCILS Section 5.2 The Modern Periodic Table The Elements by Tom Lehrer

11. The Modern Periodic Table • “Periodic” - Repeating patterns • Listed in order of increasing number of protons (atomic #) • Properties of elements repeat • Periodic Law- when elements arranged by increasing number of protons, properties repeat in pattern

12. Columns in the Periodic Table -vertical (up & down) -called groups or families -#ed 1-18 or 1A through 8A -elements in same family have similar properties

13. Rows in the Periodic Table -horizontal (left – right) -called a period -properties change greatly across period -first element in period is very active metal -last element in most periods is noble gas -7 periods (number them on your periodic table)

15. Element Key Important information about an element is given in each square of the periodic table: • its atomic number • chemical symbol • element name • average atomic mass 6CCarbon12.01 For example: Carbon has atomic # 6 (or has 6 protons), an average atomic mass of 12.01 and a symbol of C

16. Atomic Mass • Two isotopes of copper • 72% copper-63 • 28% copper-65 • Makes the average 63.56 amu

17. Determining Average Atomic Mass

18. Metals • Most solids (Hg is liquid) • Luster – shiny. • Ductile – drawn into thin wires. • Malleable – hammered into sheets. • Conductors of heat and electricity. • Include transition metals – “bridge” between elements on left & right of table

19. Non-Metals • Properties are generally opposite of metals • Poor conductors of heat and electricity • Low boiling points • Many are gases at room temperature • Solid, non-metals are brittle (break easily) • Chemical properties vary

20. Metalloids • stair-step pattern • Have properties similar to metals and non-metals • Ability to conduct heat and electricity varies with temp • Better than non-metals but not metals

21. Variation Across a Period: Left to Right • Physical and Chemical properties • Atomic size decreases • Metallic properties decrease • Ability to lose an electron decreases • Ability to gain electrons increases

23. Section 5.3 Representative Groups Hip Hop Classroom The Elements

24. What are Valence electrons? • outermost e-’s • Responsible for chem props • Elements in same group… same # of VE • ALL atoms want full outer energy level (usually 8 VE) • To get full outer energy level, some elements: • lose e- (metals) • gain e- (non-metals) • share electrons (some non-metals & metalloids)

25. Introducing the ten major groups (families) on the modern Periodic Table:

26. Alkali Metals potassium - 1 valence electron (VE) - soft, silver-white, shiny metals • never found pure • most reactive metals • Reactivity increases down group reactivity increases

27. Label the Alkali Metals to your PT

28. Alkaline Earth Metals magnesium - 2 VE - not as reactive as alkali metals • often mixed with Al • forms strong/light weight alloys

29. Alkaline Earth Metals • Magnesium • Used to make steel (light metal w/o losing strength) • photosynthesis (chlorophyll) • Calcium • bones & teeth • Chalk, limestone, pearls, plaster

30. Label the Alkaline Earth Metals to your PT

31. Boron Family -3 VE Boron • Hard/brittle • never found pure in nature • in borax...used to make detergents & cosmetics

32. Boron Family Aluminum Aluminum • most abundant metal in earth’s crust • important metal for industry • light, strong, slow to corrode 13AlAluminum26.98

33. Label the Boron Family on your PT

34. Carbon Family silicon • 4 VE • Can gain 4 e-, lose 4 e-, or share e- • Most compounds in body contain C • Si 2nd most abundant element in Earth’s crust • Si used to tip saw blades

35. Label the Carbon Family on your PT

36. Nitrogen Family Arsenic • 5 VE • Tend to gain 3 e- • N and P used in fertilizers • P on tips of matches

37. Label the Nitrogen Family on your PT

38. Oxygen Family sulfur • 6 VE • Tend to gain 2 e- • O very abundant element • S used in fertilizers • O needed for digestion

39. Label the Oxygen Family on your PT

40. Halogen Family (“salt-former”) -7 VE -most active nonmetals -never found pure in nature -react with alkali metals easily (forms salts) -F most active halogen

41. bromine Halogens cont… • F compounds in toothpaste • Cl kills bacteria • I keeps thyroid gland working properly

42. Label the Halogen Group on your Periodic Table

43. The Noble Gases (Inert Gases) Neon - non-reactive • outermost e- shell is full (8 VE) • In “neon” lights -in earth’s atmosphere (less than 1%)

44. Label the Noble Gases on your Periodic Table

45. Transition Metals mercury • Almost all solids at room temp (Hg exception) • ductile, malleable, conductors • VE varies • Less Reactive than Groups 1 & 2 • Fe, Co, and Ni produce magnetic field

46. Label the Transition Metals on your periodic table

47. uranium Rare Earth Elements • Lanthanide series (period 6) • Actinide Series (period 7) • Some radioactive • Separated from table to make easy to read/print • silver, silvery-white, or gray metals. • Conduct electricity

48. Label the Lanthanide Series on your PT

49. Label the Actinide Series on your PT

50. You may watch more videos about the elements at: http://www.periodicvideos.com/ or sing along at: http://www.youtube.com/watch?v=zGM-wSKFBpo&feature=related elemental funkiness - Mark Rosengarten hip hop classroom