1. HONORS CHEMISTRY
September 18-19, 2013

2. How do we know what the filling order is?
What chemistry tool might we rely on? (Stop)

3. Electron Configurations and the Periodic Table
Valence electron configurations repeat down a group

4. Ground state electron configurations
Example: Li
atomic number = 3
nucleus has 3 protons
neutral atom has 3 electrons
2 electrons in 1s orbital, 1 electron in 2s orbital 2s 1s

5. Different ways to show electron configuration
Energy level diagram
Box notation   2s 1s 2s 1s
Spectroscopic notation
Li 1s2 2s1
Read this “one s two” not “one s squared”
Write the superscript 1. Don’t leave it blank

6. Using the Periodic Table
The last subshell in the electron configuration is one of these
(row #) s (row # – 1) d
(row #) p (row # – 2) f

7. The f-block is inserted into to the d-block

8. Electron configuration of O
Atomic number of O = 8 so neutral atom has 8 e–

9. Electron configuration of Co
Atomic number of Co = 27 so neutral atom has 27 e–

10. Simplifying electron configurations Shorthand Noble Gas Configuration    
Build on the atom’s noble gas core
He 1s2
O 1s22s22p4
O [He]2s22p4
Ar 1s22s22p63s23p6
Co 1s22s22p63s23p64s23d7
Co [Ar]4s23d7 1s 2s 2p                1s 2s 2p 3s 3p 4s 3d

11. Noble Gases Far right of the periodic table
These elements are extremely unreactive or inert
They rarely form compounds with other elements

12. Noble Gas electron configurations
What is the electron configurations for Neon
Abbreviated way to write configurations
Start with full outer shell then add on Br Ba

13. Noble Gases
Neon- emits brilliant light when stimulated by electricity – neon signs- 4th most abundant element in the universe.
Helium- light non reactive gas- used balloons- inexpensive, plentiful and harmless
Radon- radioactive gas- can cause cancer- colorless, odorless emitted from for certain rocks underground

14. Why are we doing all of this?
Properties of atoms correlate with the number and energy of electrons
Electron configurations are used to summarize the distribution of electrons among the various orbitals

15. Electron configuration of ions
What is an ion?
How many electrons does Cl1- have?
What is the electron configuration for the chloride ion?
How many electrons does Ca2+ have?
What is the electron configuration for the calcium ion?
What do you notice?

16. Why is this important Valence electrons
Electrons in the outermost energy level
Where all the action occurs

17. The f-block is inserted into to the d-block

18. Find the electron configuration of Au
Locate Au on the periodic table

19. Find the electron configuration of Au
Au [Xe]
The noble gas core is Xe

20. Find the electron configuration of Au
Au [Xe]6s2
The noble gas core is Xe
From Xe, go 2 spaces across the s-block in the 6th row  6s2

21. Find the electron configuration of Au
Au [Xe]6s24f14
The noble gas core is Xe
From Xe, go 2 spaces across the s-block in the 6th row  6s2
Then detour to go 14 spaces across the f-block  4f14
note: for the f-block, n = row – 2 = 6 – 2 = 4

22. Find the electron configuration of Au
Au [Xe]6s24f145d9
The noble gas core is Xe
From Xe, go 2 spaces across the s-block in the 6th row  6s2
Then detour to go 14 spaces across the f-block  4f14
note: for the f-block, n = row – 2 = 6 – 2 = 4
Finally go 9 spaces into the d-block on the 6th row  5d9
note: for the d-block, n = row – 1 = 6 – 1 = 5

23. Practice Draw the orbital diagram for sulfur.
What ion does sulfur want to form and why?
Draw the orbital diagram for Potassium.

24. What does this mean
Properties of atoms correlate with the number and energy of electrons
Atoms like to have full outer shells.

25. Refer to Atomic Structure Worksheet

26. Periodic Trends

27. Preview 4 Periodic Trends 2 main factors affect periodic trends
Atomic Size/Radius
Ionic Size (**)
Ionization Energy
Electronegativity
2 main factors affect periodic trends
Number of electron shells (group)
Effective Core Charge (ECC) (period)

28. Term (Refer to Definition Sheet)
Effective Core Charge (ECC)
1) The net charge that pulls on the valence electrons in an atom. The greater the effective core charge, the greater the pull. It is determined by subtracting the number of core electrons from the number of protons in the nucleus
For example: Magnesium (label ECC on P.T.)

29. Term
Electron Shell
Pattern across the period?
Pattern down the group?

30. Periodic Trends Atomic radius
The distance from the center of an atoms nucleus to it’s outermost electron
Measure of atomic size

31. Periodic Trends Graph the first 20 elements
Periodic Trends Graph the first 20 elements. What is the trend down a group? Across a Period?
Atomic radius

32. Periodic Trends

33. Atomic Radius Group Trend Period Trend Increases from top to bottom
More energy levels or quantum levels (or “shell”) as you go down a group – atomic radius increases
Period Trend
Increases from right to left
All electrons in the same energy level. Increased # of protons holds them closer to nucleus.
Decrease in Effective Core (Nuclear) Charge (ECC)
Calculate ECC for elements in period 2

34. Table of Atomic Radii

35. Period Trend: Atomic Radius

36. Periodic Trends Size of an atom when electrons are added or removed.
Electrons removed atom becomes smaller.
Electrons added atoms become larger
Why?
Electron-Electron Repulsion
Ionic Size

37. Ionic Size Cations Anions Positively charged ions formed when
an atom of a metal loses one or
more electrons
Cations
Smaller than the corresponding
atom
Negatively charged ions formed
when nonmetallic atoms gain one
or more electrons
Anions
Larger than the corresponding
atom

38. Periodic Trends Graph the first 20 elements
Periodic Trends Graph the first 20 elements. What is the trend down a group? Across a Period?
Ionic Size (label P.T.)

39. Table of Ion Sizes

40. Ionic Size Group Trend Period Trend Increases from top to bottom
More energy levels as you go down a group – ionic size increases
Period Trend
Decreases as atoms lose more electrons
Increases dramatically as atoms start gaining electrons, decreases as atoms gain fewer electrons.

41. Periodic Trends Ionization Energy
Energy needed to remove one of the electrons on an atom’s outer shell.
How strongly does an atom hold it’s outermost electron.

42. Periodic Trends Graph the first 20 elements
Periodic Trends Graph the first 20 elements. What is the trend down a group? Across a Period?
Ionization Energy

44. Ionization Energy Group Trends Period Trend
Increases from bottom to top.
The closer outer shell electrons are to the nucleus the harder they are to remove.
Period Trend
Increases from left to right.
The more electrons in the outer shell the harder it is to remove one.
Increase in Effective Core Charge (ECC)

45. Periodic Trend: Ionization Energy

46. Periodic Trends Electronegativity
Is a measure of the level of attraction (pull) an atom exerts on the electrons of another atom.
Ability of an atom to attract electrons
Which elements want to gain electrons the most?

47. Periodic Trends Graph the first 20 elements
Periodic Trends Graph the first 20 elements. What is the trend down a group? Across a Period?
Electronegativity

49. Periodic Table of Electronegativities

50. Electronegativity Group Trend Period Trend
Increases from bottom to top
As radius decreases, electrons are closer to the nucleus (decrease in number of electron shells)
Period Trend
Increases from left to right
The more electrons in the outer shell (up to 7) the more the atom wants to attract electrons
Exception: Trend does not apply to Noble Gases
Increase in Effective Core Charge (ECC)

51. Periodic Trend: Electronegativity

52. Summarize the Trends
Questions???

53. Summary of Periodic Trends

54. Practice Se and Br P, S, Se Cl, Cl1-, Br, Br1- Mg, Mg2+, Na, Na1+
Smallest atom
Lowest Ionization Energy
P, S, Se
Largest atom
Highest Ionization Energy
Cl, Cl1-, Br, Br1-
Largest ionic size
Mg, Mg2+, Na, Na1+
Smallest ionic size

55. Atomic Properties Definitions For Quiz – Monday
Effective Core Charge:
It is the net charge that pulls on the valence electrons in an atom.
The greater the effective core charge, the greater the pull.
It is determined by subtracting the number of core electrons from the number of protons in the nucleus
Valence Electrons
Are found in the outermost, valence, electron shell (Bohr model) of the atom
Core electrons
occupy all of the inner electron, core, shells

56. Atomic Properties Definitions
Ionization Energy:
Energy needed to remove an electron from an atom or molecule.
The higher the effective core charge and lower the number of electrons shells, the greater the ionization energy
Atomic size
How big (e.g., radius) an atom is
Atomic radius is measured from the center of the nucleus to the valence electron shell.
The higher the effective core charge and lower the number of electron shells, the smaller the atom.
Electronegativity
Measure of the level of attraction (pull) an atom exerts on the electrons of another atom.
The higher the effective core charge and lower the number of electron shells, the greater the electronegativity

57. Homework Atomic Structure Worksheet 5-3 Worksheet
Study for Definition Quiz on Monday

58. Periodic Table Objective: Students know how to use the periodic table to identify alkali metals, alkaline earth metals, transition metals, metals, semimetals (metalloids), nonmetals, halogens and noble gases.

59. The Periodic Table
Dmitri Mendeleev – credited for the first periodic table in 1869.
He had put element names and a few of their properties on cards and then arranged them in various ways to help his students learn them more easily.
Arranged them so elements in the same column have similar properties.

60. Reactivity: Metal/NonMetal Trends

61. ELEMENT CLASSES

62. Periodic Song: http://www.privatehand.com/flash/elements.html
Element Images
Periodic Song:

63. Reading the periodic table
Groups or families – vertical columns
Periods – horizontal rows

65. Alkali Metals All alkali metals have 1 valence electron
They are very reactive
Reactivity of these elements increases down the group
Alkali metals: ay?docid= #
Potassium, K reacts with water and must be stored in kerosene

66. Alkaline Earth Metals
All alkaline earth metals have 2 valence electrons
Alkaline earth metals are less reactive than alkali metals
The word “alkaline” means “basic”
common bases include salts of the metals
Ca(OH)2
Mg(OH)2

67. Properties of Metals
Metals are good conductors of heat and electricity
Metals are malleable
Metals are ductile
Metals have high tensile strength
Metals have luster

68. Transition Metals
Copper, Cu, is a relatively soft metal, and a very good electrical conductor.
Mercury, Hg, is the only metal that exists as a liquid at room temperature

69. Properties of Metalloids
They have properties of both metals and nonmetals.
Metalloids are more brittle than metals, less brittle than most nonmetallic solids
Metalloids are semiconductors of electricity
Some metalloids possess metallic luster

70. Silicon, Si – A Metalloid
Silicon has metallic luster
Silicon is brittle like a nonmetal
Silicon is a semiconductor of electricity
Other metalloids include:
Boron, B
Germanium, Ge
Arsenic, As
Antimony, Sb
Tellurium, Te

71. Nonmetals Nonmetals are poor conductors of heat and electricity
Nonmetals tend to be brittle
Many nonmetals are gases at room temperature
Carbon, the graphite in “pencil lead” is a great example of a nonmetallic element.

72. Examples of Nonmetals
Microspheres of phosphorus, P, a reactive nonmetal
Sulfur, S, was once known as “brimstone”
Graphite is not the only pure form of carbon, C. Diamond is also carbon; the color comes from impurities caught within the crystal structure

73. Halogens Halogens all have 7 valence electrons
Halogens in their pure form are diatomic molecules (F2, Cl2, Br2, and I2)
Chlorine is a yellow-green poisonous gas

74. Noble Gases
Noble gases have 8 valence electrons (except helium, which has only 2)
they are chemically unreactive
Colorless, odorless and unreactive; they were among the last of the natural elements to be discovered

75. Questions?

76. White Board
Refer to Periodic Trends Review

77. Electron Configurations and Periodic Trends
Write the electron configuration and draw an orbital diagram for each element
Order each group of elements or ions based on given data for each property requested on card
Use the orbital diagrams to explain the pattern. (does it agree with the “trend”)

78. Objectives Use the periodic table to write electron configurations
Use the periodic table to obtain information about the properties of elements