1. Periodic Table
Chapter 6

2. Periodic Table Many different versions of the Periodic Table exist
All try to arrange the known elements into an organized table

3. Alternate Periodic Tables

4. Alternate Periodic Tables

5. Alternate Periodic Tables

6. Alternate Periodic Tables

7. Alternate Periodic Tables

8. Alternate Periodic Tables

9. Alternate Periodic Tables

10. Elements known since Ancient times

11. Elements Discovered in 1600’s

12. Elements Discovered in 1700’s

13. Elements Discovered

14. Elements Discovered

15. Elements Discovered

16. Elements Discovered

17. Elements Discovered

18. Elements Discovered

19. Elements Discovered since1999

20. History
Russian chemist and teacher, Dmitri Mendeleev proposed a table for organizing elements
Mendeleev arranged the elements in a table based on increasing atomic mass.

21. History
Mendeleev placed elements next to each other with similar chemical properties
He would leave elements out of order based on atomic mass if they lined up better based on chemical properties

22. History Mendeleev left spaces for elements not yet discovered
He predicted properties of elements that would fit in those spots
He predicted very closely the properties of Ge, Ga, Sc, and 5 others

23. History
British physicist, Henry Moseley, determined the atomic numbers for the elements
The modern periodic table is arranged in order of increasing atomic number.

24. Periodic Table

25. Arrangement Columns are called Groups Rows are called Periods
Numbered 1-18
Rows are called Periods
Elements in the same group have similar properties

26. Group Names Group 1 - Alkali Metals Group 2 - Alkaline earth metals
Group 17 - Halogens
Group 18 - Inert or Noble gases.

27. Group Names Groups 3-11 – Transition Metals
Bottom 2 rows – Inner Transition

28. Phases at STP Most elements are solids at STP
Hg and Br are liquids at STP
H, N, O, F, Cl and Noble Gases are all gases at STP

30. Periodic Law
Periodic Law – When elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties.

31. Valence Electrons Electrons in outermost occupied energy level
Valence Electrons are responsible for most chemical properties
Elements in the same group have similar properties because they have the same number of valence electrons

32. Classifying Elements
Elements are classified into 3 groups based on their properties:
Metals – Left and Middle
Nonmetals – Right
Metalloids - Staircase

33. Metals Good conductors of heat and electrical current
High luster or sheen
Many are ductile, meaning they can be drawn into wires
Most are malleable, meaning they can be hammered into thin sheets

34. Metals Metallic Character increases as you move towards the lower left
Most Metallic Element is Francium, Fr

35. Nonmetals
Most are gases at room temperature, some are solids, and one is liquid
Most are poor conductors
Most solids are brittle

36. Nonmetals
Non-Metallic Character increases as you move towards upper right
Most nonmetallic element is Fluorine, F

37. Metalloids B, Si, Ge, As, Sb, Te
Have properties of both metals and nonmetals, based on conditions
Exceptions:
Al and Po are metals
At is a nonmetal

39. Group Characteristics
Alkali Metals (Group 1)
H, Li, Na, K, Rb, Cs, Fr
All have 1 valence electron, tend to form +1 ions
Most reactive metals
Not found in nature by themselves, always combined with someone else
Have properties of metals but are softer and less dense

40. Group Characteristics (cont)
Alkaline Earth Metals (Group 2)
Be, Mg, Ca, Sr, Ba, Ra
All have 2 valence electrons, tend to form +2 ions
Harder and more dense than alkali metals, but also have higher melting and boiling points
Highly reactive, but not as much as alkali metals
Not found by themselves in nature

41. Group Characteristics (cont)
Halogens (Group 17)
F, Cl, Br, I, At
All have 7 valence electrons, tend to form -1 ions
Strongly non-metallic
Most active nonmetals
Have low melting and boiling points
Combine readily with metals to form salts

42. Group Characteristics (cont)
Noble Gases (Group 18)
He, Ne, Ar, Kr, Xe, Rn
Colorless gases that are extremely non-reactive
Full valence shell, non-reactive
All are found in small amounts in our atmosphere

43. Group Characteristics (cont)
Transition Metals (Groups 3-11)
Most are excellent heat and electrical conductors
Most have high melting points and are hard, except Hg
Less active than group 1 and 2 metals
Many combine with Oxygen to form oxides (Chemical property)
Many have more than one oxidation number
Form compounds that are colorful

44. Reminder STP Standard Temperature and Pressure
1 atm, 0°C
Reference Point for most measurements

45. Diatomics
Eight elements are diatomic molecules when alone in nature (exist as two atoms bonded together)
H2, N2, O2, F2, Cl2, Br2, I2, At2

46. Diatomics
Hydrogen and the Magic 7

47. Coloring
Color in the specific groups with your own color choices

48. Coloring Color in the different phases with your own color choices
Solid, Liquid, Gas, Synthetic

49. Coloring
Color in the different classifications with your own color choices
Metals, Nonmetals, Metalloids

51. Orbital Blocks
s - block
p - block
d - block
f - block

52. Periodic Trends
How a property changes either across a period or down a group
Atomic Number
Atomic Mass
Atomic Radius
Ionic Radius
Ionization Energy
Electronegativity

53. Trends Atomic number increases across a period.
Increasing number of protons
Atomic number increases down a group

54. Trends Atomic mass generally increases across a period.
Increasing protons, neutrons, and electrons.
Atomic mass increases down a group.

55. Radius Atomic Radius – measure of the size of the atom
Half the distance between two nuclei
Ionic Radius – measure of the size of an ion

56. Trends Atomic Radius decreases across a period
More protons to pull on the electrons
Atomic Radius increases down a group
Increasing electrons into more energy levels (more shells)

57. Ions Atom, or group of atoms, that has gained or lost electrons
Cation – positive ion
Anion – negative ion

58. Ions When an atom loses an electron, it becomes positively charged
The radius becomes smaller
Metals tend to lose electrons

59. Ions When an atom gains an electron, it becomes negatively charged
The radius becomes larger
Nonmetals tend to gain electrons

60. Trends Ionic Radius decreases for positive ions across a period
More protons to pull on the electrons
Ionic Radius decreases for negative ions across a period

61. Ionic Radius -3 +1 -2 +2 -1 +3 +4

62. Trends Ionic Radius increases down a group
Increasing electrons into more energy levels (more shells)

64. Ionization Energy (IE)
Amount of energy required to remove an electron from an atom
Ca  Ca+ + e kJ/mol
First ionization energy is removing the first electron
Second Ionization energy is removing the second electron after having the first removed
Ca+  Ca2+ + e kJ/mol

65. IE Trends Ionization energy tends to increase across a period
More protons are able to hold on tighter to electrons
Ionization energy tends to decrease down a group
Electrons are farther away from the protons (more shells)

66. Electronegativity (EN)
Ability of an atom to attract an electron from another atom when in a compound.
Noble gases are usually omitted since they don’t form compounds
Fluorine, F, is the most electronegative element with a value of 4.0
Francium, Fr, is the least electronegative element with a value of 0.7

67. EN Trends Electronegativity tends to increase across a period
More protons are able to attract electrons better
Electronegativity tends to decrease down a group
Electrons are farther away from the protons (more shells)

68. Trends Summary Property Period (LR) Group (TB) Atomic Number
Atomic Mass
Atomic Radius
Ionic Radius
Ionization Energy
Electronegativity

69. Reactivity
Elements that are more reactive tend to either gain or lose electrons very easily
Elements that lose electrons easily have low IE and low EN
Lower left, Fr
Elements that gain electrons easily have high IE and high EN
Upper right, F