1. + 
2 Na (s)
Cl2
2 NaCl
Ionic compound

2. The Periodic Law
In the modern periodic table, elements are arranged in order of increasing atomic number.
In the modern periodic table, the elements are arranged in order of increasing atomic number. Interpreting Diagrams How many elements are there in the second period?

3. Electronegativity vs. atomic number
04/10/99

4. Ionization energy vs. atomic number
04/10/99

5. Valence Electrons
When atoms combine, only the valence electrons are involved.
Valence electrons are the electrons in the atom’s highest occupied energy level.
The number of valence electrons largely determines the chemical properties of an element.

6. Valence Electrons
Group 1A
Group 6A
Group 7A
Group 8A
Lithium
Oxygen
Fluorine
Neon
On your handout, draw the Lewis dot structures for the representative elements in periods 1 through 4.
Sodium

7. Valence Electrons
Electron dot structures are diagrams that show valence electrons as dots.

8. The Octet Rule The Octet Rule
When forming compounds, atoms tend to achieve the electron configuration of a noble gas.
Atoms of metals tend to lose their valence electrons.
Atoms of some non-metals tend to gain electrons or to share electrons with another nonmetal.
When an atom forms an ion, it is no longer neutral, it has a charge, called its oxidation number.

9. Ion Notation HOW TO WRITE AN ION: [ELEMENT SYMBOL]Charge
Examples: Na oxidation number = +1
Cl oxidation number = -1
Al oxidation number = +3
** Charge/Oxidation number is a SUPERSCRIPT

10. Formation of Cations
Metals have LOW electronegativity and LOW ionization energy so they will LOSE electrons to form cations, positive ions.
The electron configuration of the sodium ion is the same as that of a neon atom.

11. Formation of Cations
Using electron dot structures, you can show the ionization more simply.

12. Formation of Cations
A magnesium atom attains the electron configuration of neon by losing both valence electrons. The loss of valence electrons produces a magnesium cation with a charge of 2+.

13. Formation of Anions
Non-metals have HIGH electronegativity and HIGH ionization energy so they will GAIN electrons to form anions, negative ions.
Both a chloride ion and the argon atom have an octet of electrons in their highest occupied energy levels.

14. Formation of Anions
A chlorine atom attains the electron configuration of argon by gaining an electron. The gaining of a valence electron produces a chlorine anion with a charge of 1-.

15. Formation of Anions
Oxygen is in Group 6A. How many valence electrons? What noble gas configuration will it have when it forms an ion?

16. Charges of Ions Chlorine ion: Chlorine atom: 18 electrons 18-
17 protons 17 +
Neutral 0
Chlorine ion:
18 electrons 18-
17 protons 17 +
Net charge 1-
Magnesium atom:
12 electrons 12-
12 protons 12 +
Neutral 0
Magnesium ion:
10 electrons 10-
12 protons 12 +
Net charge 2+

17. Predicting Ionic Charges
Group 1A:
Lose 1 electron to form 1+ ions
H1+
Li1+
Na1+
K1+
Rb1+

18. Predicting Ionic Charges
Group 2A:
Loses 2 electrons to form 2+ ions
Be2+
Mg2+
Ca2+
Sr2+
Ba2+

19. Predicting Ionic Charges
Loses 3
electrons to form
3+ ions
Group 3A:
B3+
Al3+
Ga3+

20. Predicting Ionic Charges
Neither! Group 4A elements rarely form ions
EXCEPTION: Sn and Pb!! Treat like transition metals
Do they lose 4 electrons or gain 4 electrons?
Group 4A:

21. Predicting Ionic Charges
Nitride
Gains 3
electrons to form
3- ions
Group 5A:
P3-
Phosphide
As3-
Arsenide

22. Predicting Ionic Charges
Oxide
Gains 2
electrons to form
2- ions
Group 6A:
S2-
Sulfide
Se2-
Selenide

23. Predicting Ionic Charges
Gains 1 electron to form
1- ions
Group 7A:
F1-
Fluoride
Br1-
Bromide
Cl1-
Chloride
I1-
Iodide

24. Predicting Ionic Charges
Stable noble gases do not form ions!
Group 8A:

25. Ions and the octet rule
04/10/99
Which ions have fewer than 8 valence electrons? H+ has 0 valence electrons Li+ has 2 valence electrons (similar to He) Be2+ has 2 valence electrons B3+ has 2 valence electrons

26. Br P Ne Al Ca Ion Ions and the octet rule Kr Ar (3) Ne (0) Ne (3)
04/10/99
Complete the chart in your handout. Br P Ne Al Ca
Nearest Noble Gas (spaces removed) Kr
Ar (3)
Ne (0)
Ne (3)
Ar (2)
(1)
Ion
Br-
P 3–
none
Al 3+
Ca 2+

27. Predicting Ionic Charges
Many transition elements have more than one possible charge. Also Pb and Sn (Group 4A)
Iron (II) = Fe2+
Note the use of Roman numerals to show charges
Iron (III) = Fe3+

28. Predicting Ionic Charges
Roman numerals:
V 5
VI 6
I 1
VII 7
II 2
VIII 8
III 3
IX 9
IV 4
X 10

29. Predicting Ionic Charges
Group B elements:
Some transition elements
have only one possible oxidation state, such as these three:
Silver = Ag1+
Zinc = Zn2+
Cadmium = Cd2+

30. Write symbols for these cations:
Potassium ion
Magnesium ion
Copper (II) ion
Oxygen ion (Oxide)
Arsenic ion (Arsenide)
Bromine ion (Bromide) K+
Mg2+
Cu2+
O2-
As3-
Br-

31. HOMEWORK #1: Write the ion symbols
Chromium (VI) ion
Barium ion
Mercury (II) ion
Phosphide
Fluoride
Oxide
Cr6+
Ba2+
Hg2+
P3- F-
O2-

32. HOMEWORK #2: 1. Write ion notation:
Nitrogen
Sulfur
Barium
Lithium
Beryllium
Iodine
N3-
S2-
Ba2+
Li+
Be2+ I-

33. HOMEWORK #2: High EN – form anions High IE – form anions
Noble gases have full valence shell

34. HOMEWORK #2: 5. How many valence electrons?Cs Rb Ga S Sr 1 3 6 2

35. HOMEWORK #2: 5. Metals or non-metals?Mg C H Zn Se
metal
non-metal

36. HOMEWORK#3: Naming Na+ Ca2+ Al3+ Fe3+ Fe2+ Mn2+ Li+ Sodium ion
Calcium ion
Aluminum ion
Iron (III) ion
Iron (II) ion
Manganese (II) ion
Lithium ion

37. Cl- N3- Br- O2- S2- Chloride Nitride Bromide Oxide Sulfide
HOMEWORK #3: Naming
Cl-
N3-
Br-
O2-
S2-
Chloride
Nitride
Bromide
Oxide
Sulfide

38. Naming Ions NAMING CATIONS (positive metal ions):
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NAMING CATIONS (positive metal ions):
Representative Elements: Just write the name of the metal.
Ca2+ = calcium ion
Transition metals (and Pb & Sn) can have more than one possible charge. Use a roman numeral to indicate the charge
Iron (II) = Fe2+ Iron (III) = Fe3+

39. Exceptions: Some of the transition metals have only one ionic charge:
Do not use roman numerals for these:
Silver is always 1+ (Ag+)
Cadmium and Zinc are always 2+ (Cd2+ and Zn2+)

40. Naming Ions NAMING ANIONS (non-metal, negative ions):
04/10/99
NAMING ANIONS (non-metal, negative ions):
Anions are always the same charge (Cl always -1)
Change the monatomic element ending to
– ide
F1- a Fluorine atom will become a Fluoride ion.
N3- a Nitrogen atom will become a Nitride ion.

41. Practice: Name these ionsK+
Mg2+
Cu2+ I-
As3-
S2-
Potassium ion
Magnesium ion
Copper (II) ion
Iodide
Arsenide
Sulfide

42. Overview: Types of Bonds
04/10/99
3 bond types : ionic, covalent and metallic.
Ionic bonding occurs between:
a metal and a non-metal. Electrons are transferred.
Covalent bonding occurs between
two non-metals. Electrons are shared.
Metallic bonding occurs between:
two metals.

43. Overview: Types of Bonds
04/10/99
Identify each compound as ionic or covalent
MgO
(ionic),
CaCl2
(ionic),
PbCl2
(ionic),
CCl4
(covalent),
CH4
(covalent)
SO2
(covalent),

44. Ionic bonding e– 1) 2) Na Cl 3) Cl– Na+ Cl– Na+
04/10/99
Ionic bonding involves 3 steps:
loss of electron(s) by a metal,
gain of electron(s) by a non-metal,
** number of electrons lost by metal = number gained by non-metal
3) attraction between positive and negative ions e– 1) 2) Na Cl 3)
Cl–
Na+
Cl–
Na+

45. Properties of Ionic Compounds
Properties of Ionic Compounds (formed between a metal and a non-metal)
What are three properties of ionic compounds?
crystalline solids at room temperature called a CRYSTAL LATTICE
high melting points.
conduct an electric current when melted or dissolved in water.
Crystalline solids are very stabel so they are hard to change ----high melting point.

46. Properties of Ionic Compounds
Ionic compounds can conduct an electric current when melted or dissolved in water.
When sodium chloride melts, the sodium and chloride ions are free to move throughout the molten salt. If a voltage is applied, positive sodium ions move to the negative electrode (the cathode), and negative chloride ions move to the positive electrode (the anode). Predicting What would happen if the voltage was applied across a solution of NaCl dissolved in water?

47. Formation of Ionic Compounds
NaCl (table salt) is arranged in a 3-D pattern = CRYSTAL LATTICE
Sodium cations and chloride anions form a repeating three-dimensional array in sodium chloride (NaCl). Inferring How does the arrangement of ions in a sodium chloride crystal help explain why the compound is so stable?

48. Formation of Ionic Compounds
Ionic Bonds
The electrostatic forces that hold ions together in ionic compounds are called ionic bonds.
Sodium loses 1 electron;
chlorine gains 1 electron

49. Ionic bonding (Li + Cl)
04/10/99
Write out the dot structures for lithium chloride. Start by writing the dot structures for each atom. Li Cl
[ Cl ]–
[Li]+
Lithium loses 1 electron;
chlorine gains 1 electron

50. Ionic bonding: Mg + O Mg + O  [Mg]2+[O]2– O Mg [ O ]2– [Mg]2+
04/10/99
Mg + O  [Mg]2+[O]2– O Mg
[ O ]2–
[Mg]2+
Magnesium loses 2 electrons;
oxygen gains 2 electrons

51. Formation of Ionic Compounds
TRANSFER OF ELECTRONS
Each calcium loses 2 electrons;
TWO chlorine atoms gain 1 electron each

52. Naming Ionic Compounds
1. Name the cation first, then anion
2. Monatomic cation = name of the element
Ca2+ = calcium ion
3. Monatomic anion = root + -ide
Cl- = chloride
CaCl2 = calcium chloride

53. Naming Ionic Compounds
(Metals with multiple oxidation states)
For transition metals use a Roman numeral in the name:
PbCl2 Pb2+ is the lead (II) cation
PbCl2 = lead (II) chloride

54. Polyatomic ions are…
Groups of atoms that stay together, have an overall charge, and one name.
Usually end in –ate or -ite
Acetate: C2H3O2-
Carbonate: CO32-
Sulfate: SO42-
Sulfite: SO32-
Nitrate: NO3-
Nitrite: NO2-
Phosphate: PO43-
Phosphite: PO33-

55. More Common Polyatomic Ions
The two polyatomic ions ending in –ide:
Hydroxide: OH-
Cyanide: CN-
Ammonium: NH4+ (One of the few positive polyatomic ions)

56. Naming Ionic Compounds with polyatomic ions
1. Name the cation first, then the anion
2. Polyatomic cation = name of the ion
NH4+ = ammonium
3. Polyatomic anion = name of the ion
SO42- = sulfate
(NH4)2SO4 = ammonium sulfate

57. Practice by writing the name for polyatomic ions Circle the anion and cation in each compound
MgSO4
NH4Cl
AlPO4
Magnesium sulfate
Ammonium chloride
Aluminum phosphate

58. Writing Ionic Compound Formulas
1.Write the symbols for the cation and anion, including CHARGES!
2. Check to see if charges are balanced.
3. Balance charges , if necessary, using subscripts. Use the criss-cross method to balance subscripts.

59. Hints:
If you need more than one polyatomic ion to balance the charges put ( ) around the ion.
If anions end in -ide they are monoatomic [Except OH-, hydroxide & CN-, cyanide]
If anion ends in -ate or –ite, then it is polyatomic

60. Writing Ionic Compound Formulas
Example: Iron (III) chloride (note the 2 word name)
1. Write the symbols for the cation and anion, including CHARGES!
Fe3+
Cl- 1 3
Now balanced.
2. Check to see if charges are balanced.
Not balanced!
= FeCl3
3. Balance charges , if necessary, using subscripts. Use the criss-cross method to balance subscripts.
4. Fe3+ + Cl-  FeCl3

61. Writing Ionic Compound Formulas
Example: Aluminum sulfide (note the 2 word name)
1. Write the symbols for the cation and anion, including CHARGES!
Al3+
S2- 2 3
2. Check to see if charges are balanced.
Now balanced.
Not balanced!
= Al2S3
3. Balance charges , if necessary, using subscripts. Use the criss-cross method to balance subscripts.

62. Writing Ionic Compound Formulas
Example: Magnesium carbonate (note the 2 word name)
1. Write the symbols for the cation and anion, including CHARGES!
Mg2+
CO32-
2. Check to see if charges are balanced.
They are balanced!
= MgCO3

63. Writing Ionic Compound Formulas
Example: Barium nitrate (note the 2 word name)
1. Write the symbols for the cation and anion, including CHARGES!
( )
Ba2+
NO3- 2 1
2. Check to see if charges are balanced.
Now balanced.
Not balanced!
3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion. Use the criss-cross method to balance subscripts.
= Ba(NO3)2

64. Writing Ionic Compound Formulas
Example: Ammonium sulfate (note the 2 word name)
( )
1. Write the symbols for the cation and anion, including CHARGES!
NH4+
SO42- 2 1
Now balanced.
2. Check to see if charges are balanced.
Not balanced!
= (NH4)2SO4
3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion. Use the criss-cross method to balance subscripts.

65. Writing Ionic Compound Formulas
Example: Zinc hydroxide (note the 2 word name)
1. Write the symbols for the cation and anion, including CHARGES!
( )
Zn2+
OH- 1 2
Now balanced.
2. Check to see if charges are balanced.
Not balanced!
= Zn(OH)2
3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion. Use the criss-cross method to balance subscripts.

66. Writing Ionic Compound Formulas
Example: Aluminum phosphate (note the 2 word name)
1. Write the symbols for the cation and anion, including CHARGES!
Al3+
PO43-
2. Check to see if charges are balanced.
They ARE balanced!
= AlPO4

67. HOMEWORK #4: Form an ionic bond?
Mg & O
As & Br
Ca & K
F & Li
Ar & H
Metal & nonmetal - YES
2 non-metals - NO
2 metals - NO
Noble gas - NO

68. HOMEWORK#5: Naming KI Potassium Iodide SnBr4 Tin (IV) Bromide Mg3P2
NaF
Al2Se3
MgBr2
KCl
Potassium Iodide
Tin (IV) Bromide
Magnesium Phosphide
Sodium Fluoride
Aluminum Selenide
Magneium Bromide
Potassium Chloride

69. HOMEWORK#5: Naming FeCl2 Iron (II) Chloride FeCl3 Iron (III) Chloride
Al2S3
Iron (II) Chloride
Iron (III) Chloride
Aluminum Sulfide

70. HOMEWORK#5: Naming PbO Lead (II) Oxide TiI4 Titanium (IV) Iodide Co3N2
Mg3P2
TiSe
Cu2O
V3P5
Zn3N2
Lead (II) Oxide
Titanium (IV) Iodide
Cobalt (II) Nitride
Magnesium Phosphide
Titanium (II) Selenide
Copper (I) Oxide
Vanadium (V) Phosphide
Zinc Nitride

71. HOMEWORK#5: Naming Li2O Lithium Oxide CuO Copper (II) Oxide PbS
Lead (II) Sulfide