1. Chemical & Physical Properties of the Elements and the Periodic Table
Chapter 6
Chemical & Physical Properties of the Elements and the Periodic Table

2. Review Quiz Chapter 6 Heats of (kJ/mol) conversion.
∆H summation formula.

3. Valence Electrons
The valence electrons are the electrons in the outer energy level (valence level).

5. Alkali Metals

6. Alkaline Earth
Metals

7. Transition Elements (Metals)

8. Halogens

9. Noble Gases

10. Inner Transition
Elements (Metals)

11. The Representative Elements

12. Covalent radius
Covalent radius is essentially the size of an atom.

13. Covalent Radii (atomic radii)
Atomic Radius

14. Ionic Radius
Ionic Radius is the size of an ion.

16. Isoelectronic Series
Substances are isoelectronic if they have the same electron configuration.
Name two isoelectronic species.

17. Ionization Energy
Ionization energy is the energy needed to remove an electron from an atom or ion.

18. First Ionization Energy
First Ionization energy is the energy needed to remove the first electron from an atom.

21. Multiple Ionization Energies
Second Ionization energy is the energy needed to remove the second electron from an atom.
Third Ionization energy is the energy needed to remove the third electron from an atom.
Etc.

22. Ionization Energies in kJ/mol1 2 3 4 5 6 7 H
1312 He
2372
5250 Li
520
7297
11810 Be
899
1757
14845
21000 B
800
2426
3659
25020
32820 C
1086
2352
4619
6221
37820
47260 N
1402
2855
4576
7473
9442
53250
64340
Write the equation representing the first ionization energy of hydrogen.

23. First Ionization Energy of H
H kJ → H+ + e-

24. Electron Affinity
The energy change that occurs when an electron is added to an atom.

25. Write the equation representing the electron affinity of hydrogen.

26. Electron Affinity of H
H + e- → H kJ

27. Effective Nuclear Charge (Zeff)
You will find many of the notes for effective nuclear charge on a sheet in your notebook titled “Effective Nuclear Charge”.
The effective nuclear charge (Zeff) of an atom is basically how well it is able to hold on to its most loosely held electron.

28. Effective Nuclear Charge (Zeff)
We can estimate the effective nuclear charge of an atom by using the following:
The nuclear charge (Z)
The shielding effect
Electron repulsions

29. The Nuclear Charge (Z) Based on the number of protons in the nucleus.
Example: Carbon vs. Nitrogen

30. The Nuclear Charge (Z)

31. The greater the number of protons in the nucleus the greater the effective nuclear charge.

32. Nuclear Charge and Zeff

33. Shielding Effect.
The shielding effect is when electrons between the nucleus and the outermost electrons in an atom shield or lessen the hold of the nucleus on the outermost electrons.

34. Shielding Effect.

35. Example of the Shielding Effect
He atom in the excited state with one electron in the 1s and one electron in the 2p.
He+ ion in the excited state with one electron in the 2p.
Ion A

36. Shielding Effect.
Shielding can be checked by writing the electron configuration.

37. Example of the Shielding Effect
He atom in the excited state with one electron in the 1s and one electron in the 2p.
He+ ion in the excited state with one electron in the 2p.
1s12p1
2p1

38. Shielding Effect Energy Levels vs. Sublevels
Energy levels have the greatest effect on shielding.
Sublevels increase shielding but to a far lesser extent.

39. Ionization Energies in kJ/mol1 2 3 4 5 6 7 H
1312 He
2372
5250 Li
520
7297
11810 Be
899
1757
14845
21000 B
800
2426
3659
25020
32820 C
1086
2352
4619
6221
37820
47260 N
1402
2855
4576
7473
9442
53250
64340

40. Zeff can help us explain the ionization energies.

41. Explain the first ionization energies of Be and B

42. Explain the first ionization energies of Be and Mg

43. Effective Nuclear Charge can be used to help explain atomic radius.

44. Explain the difference in atomic radii for Li and Be. Which are 1
Explain the difference in atomic radii for Li and Be. Which are 1.52 and 1.11 angstroms respectively.

45. Explain the difference in atomic radii for Li and Na. Which are 1
Explain the difference in atomic radii for Li and Na. Which are 1.52 and 1.86 angstroms respectively.

46. Effective Nuclear Charge can be used to help explain atomic radius.
Based on nuclear charge and shielding.

47. Electron Repulsions: Paired vs. Unpaired Electrons
A paired electron has increased electron – electron repulsion.
It is easier (takes less energy) to remove a paired electron than it does to remove an unpaired electron.
We check the pairing of electrons in the outer sublevel by writing an orbital filling diagram.

48. Nitrogen vs. Oxygen First Ionization Energy

49. Nitrogen vs. Oxygen First Ionization Energy

50. Stability Schmability
It is much harder to remove an electron from helium than it is Li. This is Illustrated by their respective ionization energies given below. Explain.
Stability Schmability
He = 2370 kJ/mol
Li = 520 kJ/mol

51. Penetration Effect
Electrons in a higher energy level can often penetrate (dive) through lower energy levels because of the attraction that the nucleus has on them.
Smaller sublevels can penetrate closer to the nucleus than larger sublevels.

52. Explain the relative energies of the sublevels within the fourth energy level.
The s sublevel penetrates closer to the nucleus followed by the p, d and the f has the least penetration. The closer to the nucleus the lower the energy and therefore the relative energies of the sublevels in the fourth energy level is:
4s < 4p < 4d < 4f.

53. Explain why a 4s sublevel has a lower energy than 3d.
A 4s sublevel penetrates closer towards the nucleus than does a 3d so even though the 3d is part of the third energy level the 4s on average is closer to the nucleus and is therefore lower in energy than the 3d.

54. Periodicity

55. Periodicity
What would you expect the properties of element 118 to be?

56. Periodicity
How do you expect the reactivity of Rb to compare to K?

57. Periodicity
How do you expect the reactivity of Rb to compare to K? Explain your answer in terms of effective nuclear charge.

59. Physical Properties of Metals
Metals are ductile (they can be drawn into wires) and metals are malleable (they can be pounded into thin sheets)
Metals have relatively high melting points and boiling points.
Metals conduct electricity and heat.
Metals are usually shiny. They have luster.
These properties can be explained by understanding the metallic bond.

60. The Metallic Bond
The metal is held together by the strong forces of attraction between the positive nuclei and the delocalized electrons in what is termed a metallic bond.
The metallic bond is sometimes described as "an array of positive ions in a sea of electrons".
If you are going to use this view, beware! Is a metal made up of atoms or ions?

61. Sodium
Atoms

62. Strength of Metallic Bonding
Metallic Bonds are formed when atomic orbitals overlap to form molecular orbitals which stretch across the entire metal.
Bonding electrons then become delocalized and move throughout these molecular orbitals.
In general the more delocalized electrons the stronger the metallic bond.

63. Strength of Metallic Bonding
Based on the number of delocalized electrons.
Example:
Explain the variation in boiling points for hydrogen (-257ºC); sodium (883ºC); magnesium (1107ºC); and iron (2750ºC); in terms of metallic bonding.

64. Hydrogen boiling point (-257ºC)
Need to overcome van der Waals forces which are much weaker than metallic bonds.

65. Boiling point sodium (883ºC)
The 3s orbitals overlap on all the atoms to form metallic bonds.
[Ne]3s1
Na+

66. Boiling point magnesium (1107ºC)
The 3s orbitals overlap on all the atoms to form metallic bonds.
[Ne]3s2
Mg2+
There are twice as many delocalized electrons as in sodium creating a stronger metallic bond and a more positive ionic charge.

67. Boiling points iron (2750ºC)
The 3s orbitals overlap on all the atoms to form metallic bonds.
[Ne]4s23d6
In transition metals the d electrons can become involved in metallic bonding allowing for a larger number of delocalized electrons and a stronger metallic bond.

68. World of Chemistry “Metals”

69. Periodic Variations
Metallic behavior increases and nonmetallic behavior decreases as we move down a group in the periodic table.

70. Metals, Nonmetals, Metalloids

71. Periodic Variations
Metallic behavior decreases and nonmetallic behavior increases as we move from left to right across a period in the periodic table.

72. Chemical Properties of Metals

74. Metals “reduce” elemental nonmetals
Na + Cl2 → NaCl

75. Nonmetals “oxidize” elemental metals and other nonmetals of lower electronegativity
Na + Cl2 → NaCl
C + O2 → CO2

76. Oxidation – Reduction (Redox)
Reduction is the decrease in oxidation number caused by the gain of electrons.
Oxidation is the increase in oxidation number caused by the loss of electrons.
A reducing agent is the substance in a redox reaction that gives up electrons and is oxidized.
A oxidizing agent is the substance in a redox reaction that gains electrons and is reduced.

77. Lose Electrons Oxidation Gain Electrons Reduction
LEO the lion says GER
Lose Electrons Oxidation
Gain Electrons Reduction

78. Oxidation – Reduction (Redox)_ +
Na + Cl2 → NaCl
Cl2 is reduced and is therefore an oxidizing agent
Na is oxidized and is therefore an reducing agent

79. Chemical Properties of Metals
Review the rest of table 6.7 and the supporting reactions on pp and have questions ready for me tomorrow.

80. Standard Reduction Potentials Table (in notebook)
Use the five substances listed below to answer questions 1 – 3.
Cl Al Hg Cr I-
1. Which of the substances are oxidizing agents?
Which substance is the strongest reducing agent?
Which substance(s) could oxidize Ag?
A piece of gold (Au) is dropped into a solution of Pb(NO3)2. Does a reaction occur? Support your answer.
A piece of cobalt (Co) is dropped into a solution of Pb(NO3)2. Does a reaction occur? Support your answer.

81. Cl Al Hg Cr I‾
Which of the substances are oxidizing agents?

82. Cl Al Hg Cr I‾
Which substance is the strongest reducing agents?

83. Cl Al Hg Cr I‾
Which substance(s) could oxidize Ag?

84. A piece of gold (Au) is dropped in a solution of Pb(NO3)2
A piece of gold (Au) is dropped in a solution of Pb(NO3)2. Does the reaction occur? Support your answer.

85. A piece of cobalt (Co) is dropped in a solution of Pb(NO3)2
A piece of cobalt (Co) is dropped in a solution of Pb(NO3)2. Does the reaction occur? Support your answer.

86. Homework
There is another practice quiz in your notebook with a corresponding redox table on the back. Do this quiz as homework.
Should be able to do all homework both in the book and on the worksheets.
Activity Series pre-lab and lab write up for tomorrow.