1. Chapter 7 “Ionic and Metallic Bonding”
Chemistry
January 14, 2011

2. Bellringer #55 (Jan 14th, 2011)
Based on what you read for your homework:
What is the rule that atoms tend to follow when forming ions?
How can you determine the number of valence electrons in an atom of a representative element?

3. Agenda (Jan 14th, 2011) Answer Bellringer #55 Check Cornell notes 7.1
Write OBJECTIVES for section 7.1
Notes/Lecture 7.1
Answer “Pair to Pair” questions
Hmwk: Section 7.1 assessment and 7.1 Wkst

4. Section Ions
OBJECTIVES:
Determine the number of valence electrons in an atom of a representative element.

5. Section Ions
OBJECTIVES:
Explain how the octet rule applies to atoms of metallic and nonmetallic elements.

6. Describe how cations form.
Section Ions
OBJECTIVES:
Describe how cations form.

7. Explain how anions form.
Section Ions
OBJECTIVES:
Explain how anions form.

8. Valence Electrons are…?
The electrons responsible for the chemical properties of atoms, and are those in the outer energy level.
Valence electrons - The s and p electrons in the outer energy level
the highest occupied energy level
Core electrons – are those in the energy levels below.

9. Keeping Track of Electrons
Atoms in the same column...
Have the same outer electron configuration.
Have the same valence electrons.
The number of valence electrons are easily determined. It is the group number for a representative element
Group 2A: Be, Mg, Ca, etc.
have 2 valence electrons

10. Pair to Pair Question #1
Determine how many valence electrons are in the following atoms:
Rubidium (Rb)
Barium (Ba)
Aluminum (Al)
Fluorine (F)
Argon (Ar)
Helium (He)
Nitrogen (N)
Sulfur (S)

11. Electron Dot diagrams are…
A way of showing & keeping track of valence electrons.
How to write them?
Write the symbol - it represents the nucleus and inner (core) electrons
Put one dot for each valence electron (8 maximum)
They don’t pair up until they have to…..what rule does this sound like?
Hund’s Rule X

12. The Electron Dot diagram for Nitrogen
Nitrogen has 5 valence electrons to show.
First we write the symbol. N
Then add 1 electron at a time to each side.
Now they are forced to pair up.
We have now written the electron dot diagram for Nitrogen.

13. The Octet Rule
In Chapter 6, we learned that noble gases are unreactive in chemical reactions
The Octet Rule: in forming compounds, atoms tend to achieve a noble gas configuration; 8 in the outer level is stable
Each noble gas has 8 electrons, except for one…..which one is it???????
Helium is an exception in Group 8A because it only has 2 electrons

14. Pair to Pair Question #2
Draw the ELECTRON DOT DIAGRAM for the following atoms:
Aluminum
Silicon
Nitrogen
Sulfur
Fluorine
Argon
Barium
Rubidium

15. Formation of Cations
Metals lose electrons to attain a noble gas configuration.
They make positive ions (cations)
If we look at the electron configuration, it makes sense to lose electrons:
Na 1s22s22p63s1 1 valence electron
Na1+ 1s22s22p6 This is a noble gas configuration with 8 electrons in the outer level.

16. Electron Dots For Cations
Metals will have few valence electrons (usually 3 or less); calcium has only 2 valence electrons Ca

17. Electron Dots For Cations
Metals will have few valence electrons
Metals will lose the valence electrons Ca

18. Electron Dots For Cations
Metals will have few valence electrons
Metals will lose the valence electrons
Forming positive ions
Ca2+
This is named the “calcium ion”.
NO DOTS are now shown for the cation.

19. Electron Dots For Cations
Let’s do Beryllium, #4
The electron configuration is: 1s22s2
Thus, it can lose 2e- (making it 2+), to be like Helium
Be = Be2+
Beryllium ion

20. Pair to Pair Question #3
Draw the ELECTRON DOT STRUCTURES for the following CATIONS:
Calcium (Ca)
Sodium (Na)
Gallium (Ga)

21. Electron Configurations: Anions
Nonmetals gain electrons to attain noble gas configuration.
They make negative ions (anions)
S = 1s22s22p63s23p4 = 6 valence electrons
S2- = 1s22s22p63s23p6 = noble gas configuration.
Halide ions are ions from chlorine or other halogens that gain electrons

22. Electron Dots For Anions
Nonmetals will have many valence electrons (usually 5 or more)
They will gain electrons to fill outer shell. 3- P
(This is called the “phosphide ion”, and should show dots)

23. Electron Dots For Anions
Let’s do Chlorine, #17
The electron configuration is: 1s22s22p63s23p5
Thus, it can gain 1e- (making it 1-), to be like Argon
Cl = Cl 1-
Chloride ion

24. Pair to Pair Question #4
Draw ELECTRON DOT STRUCTURES for the following ANIONS:
Phosphorous (P)
Bromine (Br)
Sulfur (S)

25. Stable Electron Configurations
All atoms react to try and achieve a noble gas configuration.
Noble gases have 2 s and 6 p electrons.
8 valence electrons = already stable!
This is the octet rule (8 in the outer level is particularly stable). Ar

26. Bellringer #56 (Jan 18th, 2011)
Write the ELECTRON DOT DIAGRAMS of the NEUTRAL atom AND ION for the following elements:
Bromine
Boron
Strontium
****each element should have TWO electron dot diagrams

27. Agenda Objective: Review for Semester Exam Bellringer #56
Homework Check
Results of Semester Exam: 1st attempt
Semester Exam Study Guide
Science Fair Make-Up Update
Homework: Cornell Notes 7.2
Semester Exam 2nd Attempt: Tomorrow

28. Bellringer #57 (Jan 20th, 2011) According to Section 7.2
What is an IONIC COMPOUND?
What are three properties of ionic compounds?

29. Agenda (Jan 20th, 2011) Bellringer #57
Homework Check: 7.2 Cornell Notes
Write Section 7.2 Objectives
7.2 Notes/Lecture
Peer-to-Peer Questions (turn in at end of class)
Homework: 7.2 Section Assessment (#14-22)

30. Section 7.2 Ionic Bonds and Ionic Compounds
OBJECTIVES:
Explain the electrical charge of an ionic compound.

31. Section 7.2 Ionic Bonds and Ionic Compounds
OBJECTIVES:
Describe three properties of ionic compounds.

32. Ionic Compounds
Also called SALTS
Made from: a CATION with an ANION (or literally from a metal combining with a nonmetal)

33. Ionic Bonding
Anions and cations are held together by opposite charges (+ and -)
Ionic compounds are called salts.
Simplest ratio of elements in an ionic compound is called the formula unit.
The bond is formed through the transfer of electrons (lose and gain)
Electrons are transferred to achieve noble gas configuration.

34. Na Cl Ionic Bonding Example
The metal (sodium) tends to lose its one electron from the outer level.
The nonmetal (chlorine) needs to gain one more to fill its outer level, and will accept the one electron that sodium is going to lose.

35. Na+ Cl - Ionic Bonding Example
Note: Remember that NO DOTS are now shown for the cation!

36. Ca P Ionic Bonding Example
Lets do an example by combining calcium and phosphorus: Ca P
All the electrons must be accounted for, and each atom will have a noble gas configuration (which is stable).

37. Ionic Bonding Ca P

38. Ionic Bonding
Ca2+ P

39. Ionic Bonding
Ca2+ P Ca

40. Ionic Bonding
Ca2+
P 3- Ca

41. Ionic Bonding
Ca2+
P 3- Ca P

42. Ionic Bonding
Ca2+
P 3-
Ca2+ P

43. Ionic Bonding Ca
Ca2+
P 3-
Ca2+ P

44. Ionic Bonding Ca
Ca2+
P 3-
Ca2+ P

45. Ionic Bonding
Ca2+
Ca2+
P 3-
Ca2+
P 3-

46. Ca2+ P3- Ca3P2 Ionic Bonding
If you want to predict ionic bonding quickly…
Ca3P2

47. = Ca3P2 Ionic Bonding Formula Unit
This is a chemical formula, which shows the kinds and numbers of atoms in the smallest representative particle of the substance.
For an ionic compound, the smallest representative particle is called a: Formula Unit

48. Ionic Bonding
Cl-
Na+
Another example… both have single charges
NaCl

49. Mg2+ F- Mg F2 Ionic Bonding REMEMBER
If you want to predict ionic bonding quickly…
Mg F2

50. Ti4+ O2- Ti O2 Ionic Bonding
But be careful! It can be like balancing a fraction!
TiO2, not Ti2O4
Ti O2

51. Peer-to-Peer Question #1
Draw the FORMULA UNIT for the following atoms when they create an ionic bond:
Mg and Cl
Al and O
K and Br
Li and O

52. Properties of Ionic Compounds
Crystalline solids - a regular repeating arrangement of ions in the solid: Fig. 7.9, page 197
Ions are strongly bonded together.
Structure is rigid.
High melting points
Coordination number- number of ions of opposite charge surrounding it

53. NaCl CsCl TiO2 - Page 198 Coordination Numbers:
Both the sodium and chlorine have 6
NaCl
Both the cesium and chlorine have 8
CsCl
Each titanium has 6, and each oxygen has 3
TiO2

54. Do they Conduct?
Conducting electricity means allowing charges to move.
In a solid, the ions are locked in place.
Ionic solids are insulators.
When melted, the ions can move around.
Melted ionic compounds conduct.
NaCl: must get to about 800 ºC.
Dissolved in water, they also conduct (free to move in aqueous solutions)
Ex: Salt water conducts electricity but WATER alone does NOT

55. - Page 198
The ions are free to move when they are molten (or in aqueous solution), and thus they are able to conduct the electric current.

56. Bellringer #58 (Jan 21st, 2011)
Determine the formula and name for when the following atoms combine to create IONIC COMPOUNDS:
Ca and O
Al and S
K and N

57. Agenda (Jan 21st, 2011) Bellringer #58 Homework Check
2nd attempt distribution and discussion
Review for Semester Exam
Homework: Study Guide for EXTRA CREDIT IF YOU PASS!!!!!!
Extra study guide available on homework website…..VERY helpful!

58. Bellringer #59 (Jan 24th, 2011)
Determine the electron configuration for the following atoms:
Phosphorous
Fluorine
Calcium

59. Bellringer #1 (Jan 31st, 2011)
Name three things you know about ionic compounds.

60. Agenda (Jan 31st, 2011) Bellringer #1 Discuss new semester
Objective: Learn how to name ionic compounds from transition metal ions
Work on Chapter 7 Section Assessment: pg. 207 #30-47
Hmwk: Cornell Notes 7.3
Mini Quiz Tomorrow

61. New Semester…..New Beginnings
New Semester: Everyone starts all over again
Starting at BR #1: Collecting BR #1-59 TOMORROW
Late Work Policy: accept homework 1 DAY LATE. Work MUST have a note on it as to WHY it is late and personally hand to Ms. Ingham.
Don’t wait too late to ask for help. This semester WILL BE harder than last.
Homework Board in back of room WILL BE updated.

62. Cornell Notes
Cornell Notes MUST include the following for COMPLETE credit:
Answer KEY CONCEPT questions.
Define ALL vocabulary in the section AND give a picture and/or example.
Write notes for EVERY RED heading in the section.
All notes MUST end with a brief summary discussing the main points of the section. (If you take good notes, this should not be hard to do.)

63. Ionic Compounds With Transition Metals
The charges for transition metals are not as easy to predict as the metals from representative elements.
Ex: Copper can have a charge of 1+ or 2+ (Cu1+ or Cu2+)
For this reason you MUST be given the charge of the ion from a transition metal if you are going to create a ionic compound
Ex: Ti4+ and O

64. Ion Examples Symbol Name Cu+ Copper (I) ion Cu2+ Copper (II) ion Fe2+
Iron (II) ion
Fe3+
Iron (III) ion
Pb2+
Lead (II) ion
Pb4+
Lead (IV) ion
Sn2+
Tin (II) ion
Sn4+
Tin (IV) ion

65. #1:Complete the table below (turn in at end of class).
Symbol
Name
Cr2+
Chromium (III) ion
Mn2+
Manganese (III) ion
Cobalt (II) ion
Co3+

66. Predicting Ionic Compounds and Charges of Transition Metals
What Copper ion would create CuO?
What Copper ion would create Cu2O?

67. #2: Predict the ion that would create the compound below, then name the compound.
SnF2
SnS2
Fe2O3

68. What Next? Turn in questions #1 and #2
Begin work on pg.207 (unfinished work is homework along with Cornell notes)
Mini Quiz Tomorrow
Bellringers #1-59 due TOMORROW

69. Bellringer #2
Write THREE things you know about metals.

70. Agenda (Feb 1st, 2011) Bellringer #2 Homework Check
1st Semester BR Collection
Write 7.3 Objectives
7.3 Overview
Mini Quiz
Hmwk: 7.3 Section Assessment #23-29 and Writing Activity

71. Section 7.3 Bonding in Metals
OBJECTIVES:
Model the valence electrons of metal atoms.

72. Section 7.3 Bonding in Metals
OBJECTIVES:
Describe the arrangement of atoms in a metal.

73. Section 7.3 Bonding in Metals
OBJECTIVES:
Explain the importance of alloys.

74. Metallic Bonds are… How metal atoms are held together in the solid.
Metals hold on to their valence electrons very weakly.
Think of them as positive ions (cations) floating in a sea of electrons: Fig. 7.12, p.201

75. Sea of Electrons + Electrons are free to move through the solid.
Metals conduct electricity. +

76. Metals are Malleable
Hammered into shape (bend).
Also ductile - drawn into wires.
Both malleability and ductility explained in terms of the mobility of the valence electrons

77. Due to the mobility of the valence electrons, metals have:
- Page 201
Due to the mobility of the valence electrons, metals have:
Notice that the ionic crystal breaks due to ion repulsion!
1) Ductility
2) Malleability
and

78. Malleable +
Force

79. Malleable + + + + Force + + + + + + + +
Mobile electrons allow atoms to slide by, sort of like ball bearings in oil. + + + +
Force + + + + + + + +

80. Ionic solids are brittle
Force + -

81. Ionic solids are brittle
Strong Repulsion breaks a crystal apart, due to similar ions being next to each other. + -
Force + - + - + -

82. Crystalline structure of metal (pg. 202)
If made of one kind of atom, metals are among the simplest crystals; very compact & orderly
Note Fig. 7.14, p.202 for types:
1. Body-centered cubic:
every atom (except those on the surface) has 8 neighbors
Na, K, Fe, Cr, W

83. Crystalline structure of metal (pg.202)
2. Face-centered cubic:
every atom has 12 neighbors
Cu, Ag, Au, Al, Pb
3. Hexagonal close-packed
every atom also has 12 neighbors
different pattern due to hexagonal
Mg, Zn, Cd

84. Alloys We use lots of metals every day, but few are pure metals
Alloys are mixtures of 2 or more elements, at least 1 is a metal
made by melting a mixture of the ingredients, then cooling
Brass: an alloy of Cu and Zn
Bronze: Cu and Sn

85. Why use alloys? Properties are often superior to the pure element
Sterling silver (92.5% Ag, 7.5% Cu) is harder and more durable than pure Ag, but still soft enough to make jewelry and tableware
Steels are very important alloys
corrosion resistant, ductility, hardness, toughness, cost

86. More about Alloys… Table 7.3, p.203 – lists a few alloys
Types? a) substitutional alloy- the atoms in the components are about the same size
b) interstitial alloy- the atomic sizes quite different; smaller atoms fit into the spaces between larger
“Amalgam”- dental use, contains Hg

87. End of Chapter 7