1. Ionic Compounds
and
Ionic Bonding

2. Chemical Bonds There are three basic types of bonds:
Ionic - The electrostatic attraction between ions
Covalent - The sharing of electrons between atoms
Metallic - Each metal atom bonds to other metals atoms within a "sea" of 
electrons (covered in a later unit)

3. Periodic Table - Review
The periodic table is "periodic" because of certain trends that are 
seen in the elements.
Properties of elements are functions of their atomic number.
Elements from the same family/group have similar physical and 
chemical properties.
Atoms are listed on the periodic table in rows, based on number 
of protons, which is equal to the number of electrons in a neutral 
atom.

4. The Periodic Table of the Elements
The periodic table can be also divided into metals (left/blue) and 
nonmetals (right/yellow).
A few elements retain some of the properties of metals and 
nonmetals, they are called metalloids (staircase/pink). As B Si Te Ge Sb ?

5. In the periodic table, the elements are arranged in __________.1
In the periodic table, the elements are arranged in 
__________. A
alphabetical order B
order of increasing atomic number C
order of increasing metallic properties D
order of increasing neutron content E
reverse alphabetical order F
I don't know how to answer this.

6. 2
Elements __________ exhibit similar physical 
and chemical properties. A
with similar chemical symbols B
with similar atomic masses C
in the same period of the periodic table D
on opposite sides of the periodic table E
in the same group of the periodic table F
I don't know how to answer this.

7. 3
Which pair of elements would you expect to 
exhibit the greatest similarity in their physical 
and chemical properties? A
H, Li B
Cs, Ba C
Ca, Si D
Ga, Ge E
C, O F
I don't know how to answer this.

8. Which one of the following is a nonmetal?4
Which one of the following is a nonmetal? A W B Sr C Os D Ir E S F
I don't know how to answer this.

9. 5 Potassium is a __________ and chlorine is a __________. E F B D A C
metal, nonmetal B
metal, metal C
metal, metalloid D
metalloid, nonmetal E
nonmetal, metal F
I don't know how to answer this.

10. Review: Octet Rule
Atoms tend towards having complete outer shells of 
electrons (remember stability).
A full outer shell will have:
 2 electrons in the s subshell and
 6 electrons in the p subshell ( s2p6 configuration)
Octet rule: atoms tend towards having a total of 8 electrons
8 valence electrons make an octet

11. Valence Electrons
Valence electrons are the electrons in the 
highest occupied energy level of an 
element’s atoms.
The number of valence electrons largely 
determines the chemical properties of an 
element.
Valence
electron
To find the number of valence electrons in an atom of a 
representative element, simply look at its group number.
Atoms in group 3 have 3 valence electrons,
atoms in group 17 have 7 valence electrons, etc.

12. Valence Electrons Number of valence electrons in neutral atoms:
1 - 4
There is one exception:
helium has only 2 valence electrons.

13. C 3 7 27 5 B D E A 6 How many valence electrons does Aluminum have?
I don't know how to answer this.

14. D 3 E 52 C A 1 B 2 7 How many valence electrons does Barium have?
I don't know how to answer this.

15. Ions
Cations are positive and are formed by elements on the 
left side of the periodic chart 
(metals).
Anions are negative and 
are formed by elements on 
the right side of the periodic 
chart (nonmetals).

16. The Formation of Cations
Metals usually give up valence electrons
This results in a noble gas (8 electron) outer shell.
Na : 1s2 2s2 2p6 3s Na+1 : 1s2 2s2 2p6
Loss of valence 
electrons
Ne atom
The configuration of the Sodium ion is the same as Neon

17. The Formation of Cations
Na atom
Na+ ion
loses e-
11p
11e-
10e-

18. (+2 indicates 2 units of positive charge)
The Formation of Cations
Cations of Group 1A elements always 
have a charge of 1+.
Cations of Group 2A elements always 
have a charge of 2+. Mg
Mg2+
2e- +
Magnesium atom
(electrically
neutral,
charge = 0)
Magnesium ion
(+2 indicates 2 
units of positive 
charge)
(2 in front of e- indicates 2 units of 
negative charge)

19. The Formation of Anions
Nonmetals usually gain valence electrons.
This results in a noble gas (8 electrons) outer shell
Cl: 1s2 2s2 2p6 3s2 3p5
Cl- 1s2, 2s2, 2p6, 3s2, 3p6
Ar atom
A chloride ion has the same electron configuration as argon.

20. The Formation of Anions
Cl atom
Cl- ion
Gains an e-
17P
17e-
17p
18e-

21. The Formation of Anions
Anions of Group 15 (5A) elements 
have a charge of 3-
Anions of Group 16 (6A) elements 
always have a charge of 2-
Anions of Group 17 (7A) elements 
have a charge of 1-

22. 8
Metals tend to __________ electrons and 
cations tend to __________ electrons. A
gain, gain B
lose, lose C
gain, lose D
lose, gain E
neither, they keep their electrons F
I don't know how to answer this.

23. 9 Anions tend to be __________ and cations tend to be __________. A E
metals, metals B
nonmetals, nonmetals C
metals, nonmetals D
nonmetals, metals E
metalloids, metalloids F
I don't know how to answer this.

24. 10
Metals lose electrons to form cations
True
False

25. 11
Anions are formed from nonmetals
True
False

26. 12
Nonmetals tend to lose electrons forming ions
True
False

27. 13
This is the ion formed from a calcium atom A
Ca+ B
Ca2+ C
Ca- D
Ca2- E
I don't know how to answer this.

28. 14
Barium forms an ion with a charge of __________. A 1+ B 2- C 3+ D 3- E 2+ F
I don't know how to answer this.

29. Aluminum forms an ion with a charge of __________.15
Aluminum forms an ion with a charge of 
__________. A 2+ B 1- C 3+ D 2- E F
I don't know how to answer this.

30. 16
Of the following, __________ contains the 
greatest number of electrons. A
P3+ B P C
P2- D
P3- E
P2+ F
I don't know how to answer this.

31. D E 3+ F 17 3- Oxygen forms an ion with a charge of __________. A 2- CB 2+ C 3- D 3+ E 6+ F
I don't know how to answer this.

32. 18 B E 1- F Iodine forms an ion with a charge of __________. A 7- 1+2- D 2+ E 1- F
I don't know how to answer this.

33. C D E A N3- B N2- N3+ 19 I don't know how to answer this.
This is the ion formed from nitrogen A N- B
N2- C
N3+ D
N3- E
I don't know how to answer this.

34. 20 Predict the charge of the most stable ion of S? E F 2-3+ B 1- C 6+ D 2+ E 2- F
I don't know how to answer this.

35. Ionic Bonding
Electronegativity is how strongly an atom attracts electrons.
Atoms with a high electronegativity will be able to attract electrons 
away from atoms with a much lower electronegativity.
This removal of electrons can occur when the difference in 
electronegativity between the two atoms is approximately 1.7 or 
higher.
Once a positive and negative ion are formed, they will be 
attracted to each other via the electrostatic force:   r2
F = k q1 q2  
Note: The heavier nonmetals 
from 4,6,5th groups
( In, Tl, Sn, Pb, Sb Bi )
may act like metals

36. Ionic Bonding
An electronegativity difference of 
approximately 1.7 can only occur 
between a metal and a nonmetal.

37. 21 Which pair of atoms will form an ionic bond? D C E A B Li and Ne
K and Br C
K and Cs D
S and Cl E
I don't know 
how to 
answer this.

38. 22 Which pair of atoms will form an ionic bond? C A D E Li and Be B
Na and Mg C
K and Ca D
Na and Cl E
I don't know 
how to 
answer this.

39. 23
Which of the following compounds would you 
expect to be ionic? A
H2O B
CO2 C
SrCl2 D
SO2 E
H2S F
I don't know how to answer this.

40. Formation of Ionic Compounds
Compounds composed of cations and anions are called ionic 
compounds.
Although they are composed of ions, ionic compounds are electrically neutral.
The electrostatic forces that hold ions together in ionic 
compounds are called ionic bonds.

41. Ionic Bonds
When sodium and chlorine are close together, sodium's valence electron 
flies off and "harpoons" the chlorine atom.
The result is a sodium cation (+) next to a chloride anion (-)
These oppositely charged two ions attract: they reel one another together 
to form an ionic bond.
1s2 2s2 2s2 2p6 3s1 1s2 2s2 2p6 3s2 3p s2 2s2 2p6 1s2 2s2 2p6 3s2 3p6 Na Cl
Na+
Cl-
1s2 2s2 2p6 1s2 2s2 2p6 3s2 3p6 Ne Ar

42. click here for an animation of this reaction
Ionic Bonds
The electron transfer process in creating an ionic bond: Na Cl
The dots represents the valence electrons in an atom.
click here for an 
animation of this reaction

43. Formula Units
A chemical formula shows the 
kinds and numbers of atoms in 
the smallest representative unit of 
a substance.
A formula unit is the lowest 
whole-number ratio of ions in an 
ionic compound.
Every ionic compound has a 3D 
array of positive and negative 
ions.

44. Properties of Ionic Compounds
[*]
Properties of Ionic Compounds
They are crystalline solids at room temperature
They have high melting points
They conduct electricity when melted (molten) or dissolved in water (aqueous)

45. of potassium and oxygen?
Predicting an Ionic Compound Formula
Predicting the formula of the ionic compound
Potassium (K) with an electronegativity of 0.8 and oxygen (O) with 
an electronegativity of 3.5 will form an ionic compound.
What is the formula for an ionic compound
of potassium and oxygen?
How many additional valence electrons does oxygen want? 2
How many valence electrons does potassium have? 1
How many potassium atoms will it take to give oxygen the electrons it 
needs? 
The formula unit is K2O K O
Always Metal First (low electonegativity)

46. Mg Predicting an Ionic Compound Formula N
Predicting the formula of the ionic compound
Predicting an Ionic Compound Formula
What is the formula for an ionic
compound of Mg and N?
How many additional valence electrons does N want? 3
How many valence electrons does Mg have to offer? 2
How many Mg atoms will it take to give how many N the 
electrons it needs? (Find the lowest common multiplier first.)
3 Mg : 2 N
The formula unit is Mg3N2 Mg N

47. Alternate Method
If you don't like finding least common multipliers, you can 
use this alternative method:
1. Write down the ions side by side along with their 
charge. Always write the metal first.
2. "Criss-cross" the numerical values of the charges.
3. Reduce subscripts to lowest ratio. Mg N

48. Predicting an Ionic Compound Formula
Example: Write the formula for calcium sulfide.
Step 1: Identify the cation & write its common ion
  Calcium is in group 2   Ca2+
Step 2: Identify the anion & write its formula
 Sulfur is in group 6   S2-
Step 3: Criss-cross; reduce subscripts if necessary
Ca S2-
Ca2S2
CaS

49. Predicting an Ionic Compound Formula
What is the compound formed between Mg and S?
Always use the lowest ratio of the ions!
MgS
Mg S-2
Mg2S2

50. B D E A C OCs2 OCs2 I don't know how to do this. CsO2 Cs2O 24
The formula for the ionic between Cs and O is: A
CsO2 B
OCs2 C
Cs2O D
OCs2 E
I don't know how to do this.

51. C D E A B Ca2N2 Ca3N2 Ca2N3 I don't know how to do this. CaN 25
The ionic compound between Ca and N is: A
CaN B
Ca2N2 C
Ca3N2 D
Ca2N3 E
I don't know how to do this.

52. B C D E A AlO Al2O2 Al2O3 Al3O2 26 The ionic compound between Al and O
I don't know how to do this.

53. C D E A B CaAl Ca3Al2 Al2Ca3 27 No compound is formed.
What is the ionic compound formed between 
Ca and Al? A
CaAl B
Ca3Al2 C
Al2Ca3 D
No compound is formed. E
I don't know how to do this.

54. B D E A C P3Br BrP (BrP)2 no ionic compound28
What is the ionic compound formed between 
P and Br? A
P3Br B
BrP C
no ionic compound D
(BrP)2 E
I don't know how to do this.

55. 29
What is the formula for sodium phosphide? A
SP3 B
NaP C
Na3P D
NaP3 E
I don't know how to do this.

56. D E B C A BrSr2 SrBr2 Sr2Br SrBr 30 I don't know how to do this.
What is the formula for strontium bromide? A
SrBr B
SrBr2 C
Sr2Br D
BrSr2 E
I don't know how to do this.

57. 31
The formula for barium sulfide is Ba2S2.
True
False

58. Naming Binary Ionic Compounds - Cations
Many cations have the same name as the original, neutral atom.
Charge formula name
______________________________
H Hydrogen ion
Li Lithium ion
K Potassium ion
Cs Cesium ion
Ag Silver ion
Mg Magnesium ion
Ca Calcium ion
Ba Barium ion
Zn Zinc ion
Cd Cadmium ion
Al Aluminum ion

59. Naming Binary Ionic Compounds - Anions
All monoatomic anions all end in "-ide".
The ions that are produced from Group 7A (or 17)
elements are called halide ions.
Group    Group   Group
Nitride    N3-   Oxide O Fluoride F-
Phosphide 
P3-  Sulfide S Chloride Cl-
     
Iodide  I-
Bromide Br-

60. Naming Binary Ionic Compounds
Binary (two-element) compounds are named by writing the 
name of the cation followed by the name of the anion.
The name of the cation is the same as the metal name.
The name of the anion is the name of the non-metal with
the suffix changed to -ide.
Binary compounds end in "-ide."
Examples:
NaCl = sodium chloride
KI = potassium iodide
Li2S = lithium sulfide

61. E D A 32 Na2S is B C I don't know how to do this. Sodium sulfate
Sodium sulfide C
Di-sodium sulfide D
Sulfur nitride E
I don't know how to do this.

62. D E C F 33 A The correct name for SrO is __________. strontium oxide B
strontium hydroxide C
strontium peroxide D
strontium monoxide E
strontium dioxide F
I don't know how to do this.

63. D A B C E F 34 dialuminum oxide aluminum oxide
The correct name for Al2O3 is __________. A
aluminum trioxide B
dialuminum oxide C
dialuminum trioxide D
aluminum oxide E
aluminum hydroxide F
I don't know how to do this.

64. Cations formed by Transition Elements
Recall that s-block metals have only one possible ionic 
charge, based on the Octet Rule.
However, most transition metals can have more than 
one ionic charge. For this reason, there is a system for 
designating each ion.
Sn, Pb from the p block will form more than one type 
of ions and behave like transition metals.

65. Cations Formed by Transition Elements
Only common transition 
metals are shown.
Silver, cadmium and zinc only form one cation, Ag+, Cd2+ and Zn2+
Note the mercury cations.
Tin and Lead act like transition metals.

66. Cations formed by Transition Elements
We will use the Stock naming system (Roman numerals) to 
name transition metals.
Formula Name
_____________________________
Cu Copper (I) ion
Co Cobalt (II) ion
Fe Iron (II) ion
Mn Manganese (II) ion
Pb lead (II) ion
Cr Chromium (III) ion
Fe Iron (III) ion

67. Writing Formulas with Transition Metals
The charge on the cation is indicated by the Roman numeral, as 
shown in this example.  
Iron (III) oxide 
Write ion formulas.
Fe3+ O2-
Fe3+ O2-
Criss-cross charges.
 
Fe2O3
Reduce if necessary.

68. Writing Formulas with Transition Metals
The charge on the cation is indicated by the Roman numeral, as 
shown in this example.
Tin (IV) oxide    
   
Write ion formulas.
Criss-cross charges.
 Reduce if necessary. 
 SnO2
 Sn2O4
 Sn4+ O2-
 Sn4+ O2-  

69. 35
Which metal is capable of forming more than 
one cation? A K B Cs C Ba D Al E Sn F
I don't know how to answer this.

70. 36
Which metal is not capable of forming more than one cation? A Cu B Au C Fe D Sn E Al F
I don't know how to answer this.

71. D C A B iron (III) chloride 37 iron (II) chloride The name of FeCl3 is
iron chloride B
iron (II) chloride C
iron (III) chloride D
I don't know how to answer this.

72. Total cation charge + Total anion charge = 0
Formulas with Transition Metals
In order to correctly name a formula containing a transition 
metal, it is necessary to first determine the charge on the cation.
Since all compounds are neutral, then the total positive cation 
charge must equal the total negative anion charge.
In other words:
 Total cation charge + Total anion charge = 0
(charge of cation) (# of cations) + (charge of anion) (# of anions) = 0

73. Example Formula with Transition Metals
In the case of FeCl3, we make the following substitutions:
(charge of cation) (# of cations) +(charge of anion) (# of anions) = 0
(x) (1) + (-1) (3) = 0
Thus x = 3 and the cation is Fe3+ or iron(III).

74. Formulas with Transition Metals
A short cut method is to "uncriss-cross" the ions, but you 
must always double check your ions (or you'll get in 
trouble!).
FeCl3: Fe1  Cl3    
Fe3+ Cl1-
Cl does form a 1-ion
and Fe3+ is Iron (III)
 Iron (III) Cloride
Uncriss-cross.
Check the ions

75. (this formula had to be reduced from Cr2O2)
Formulas with Transition Metals
 Cr1 O1   
CrO: 
Uncriss-cross.
O forms a 2- ion
and
Cr+ does not exist!
(this formula had to be reduced from Cr2O2)
 Cromium (II) Oxide
Cr+ O-
Check the ions
Here's another practice problem.

76. E B A C D SnO 38 SnO Sn2O The formula for tin (IV) oxide is SnO2
[*] 38
The formula for tin (IV) oxide is A
SnO B
Sn2O C
SnO2 D
SnO E
I don't know how to answer this.

77. E A B C Cu2 S2 D 39 CuS2 (CuS)2 The formula for copper (II) sulfide is
I don't know how to answer this.

78. F E D C Cu3Cl2 B A Cu2Cl2 Cu2Cl CuCl2 40 CuCl
Which one of the following compounds is 
copper(I) chloride? A
CuCl B
CuCl2 C
Cu2Cl D
Cu2Cl2 E
Cu3Cl2 F
I don't know how to answer this.

79. 41
The charge on the cation in the salt Fe2O3 is __________. A 1+ B 2+ C 3+ D 5- E 6- F
I don't know how to answer this.

80. E A B C D 2+ 2- 4+ 42 What is the charge on zirconium ion in ZrO2 ? 1+
[*] 42
What is the charge on zirconium ion in ZrO2 ? A 2+ B 4+ C 1+ D 2- E
I don't know how to answer this.

81. Polyatomic Ions
A polyatomic ion is a group of atoms bonded together that have a 
charge and acts like a single unit or ion.
They are not free compounds and are not found free in nature.
They are found combined with other ions.
Eg: Sulfate = (SO4 )2-
Nitrate = (NO3) -
Carbonate = (CO3) 2-
Notes: 
 Use " ( ) " to keep the atoms together.
 Do not change the subscripts inside the "( )"

82. Examples: sulfite /sulfate
Polyatomic Ions (con't)
Most of the polyatomic ions contain oxygen atoms.
Many anions names end with “-ite” or “-ate”
In “ite/ate” pairs, the ion with fewer oxygen atoms
will have the “ite” ending
Examples: sulfite /sulfate
 nitrite /nitrate
Note that the suffix does not indicate the actual number 
of O atoms.

83. Polyatomic Ions (cont.)
Familiarize yourself with the polyatomic ions on your reference sheet
Be careful of -ide, -ite, and -ate!
H+ = proton
or hydrogen ion
or bicarbonate ]

84. CaCO3 calcium carbonate (in eggshells)
Naming Ternary Ionic Compounds
Ternary ionic compounds contain three or more different 
elements due to the presence of polyatomic ion(s).
Just as in binary ionic compounds, the name of the cation is 
given first, followed by the name of the anion.
Names of ternary compounds often end in -ite or -ate.
Examples
 CaCO3  calcium carbonate (in eggshells)
 Zn(C2H3O2)2  zinc acetate
 AgNO3 silver nitrate
 Na2SO3 sodium sulfite

85. Ternary Ionic Compounds
Writing Formulas for
Ternary Ionic Compounds
Ternary ionic compounds are neutral, just like binary ionic 
compounds. Therefore, the goal is to find the lowest ratio of 
cations to anions that will yield a neutral compound. This ratio is 
represented in a formula unit.
Examples of formula units
Ca(CO3 ) Zn(C2H3O2)2
Ag(NO3)  Na2(SO3) 

86. Ternary Ionic Compounds (con't)
Writing Formulas for
Ternary Ionic Compounds (con't)
To write a formula, the criss-cross method can again be used.
Example: Write the formula for lithium phosphate.
Step 1: Identify the cation & write its formula
 Lithium is in group 1  --> Li +
Step 2: Identify the anion & write its formula
 Phosphate is a polyatomic ion --> PO43-
Step 3: Criss-cross; reduce subscripts if necessary
Li1+
PO43-
Li3(PO4)1 or simply Li3(PO4)

87. Ternary Ionic Compounds
Writing Formulas for
Ternary Ionic Compounds
Example: Write the formula for calcium nitrite.
Ca2+
(NO3)-
Ca(NO3)2
When writing formulas with polyatomic ions, there are two important 
things to remember:
1) It is helpful to use " ( ) " to keep the atoms together,
 keeping the charge OUTSIDE the ( )
 For example:
 nitrate   (NO3)1-
 carbonate  (CO3) 2-
2) NEVER alter any symbols or subscripts INSIDE inside the "( )"

88. E D B A C 43 Na(HO) The formula for sodium hydroxide is Na(OH) Na(OH2)
I don't know how to answer this.

89. E A B C D 44 The formula for aluminum phosphate is: Al(PO4 ) Al3(PO4)
I don't know how to answer this.

90. E B A D C 45 Mg(CO3) The formula for magnesium carbonate is : Mg(CO3)2
I don't know how to answer this.

91. E A C D 46 B Ca(SO3) The formula for calcium sulfate is Ca(SO4)
I don't know how to answer this.

92. E C sodium chlorite D B 47 NaClO is A sodium chloride
sodium chlorate B
sodium chloride C
sodium chlorite D
sodium hypochlorite E
I don't know how to answer this.

93. E B 48 Mg(HCO3)2 is A C I don't know how to answer this.
Magnesium carbonate B
Magnesium hydrogen carbonate C
Magnesium hydroxide D
Magnesium carboxide E
I don't know how to answer this.

94. E A B C D 49 (NH4)(CO3) Ammonium carbonate is (NH4)2(CO3) (NH4)(CO3)2
I don't know how to answer this.

95. Writing Formulas for Ionic Compounds
PRACTICE
Writing Formulas for Ionic Compounds
Complete the table by filling in the formula for the ionic compound 
formed by each pair of cations and anions, as shown for the first pair.

96. Writing Formulas for Ionic Compounds
PRACTICE
Writing Formulas for Ionic Compounds
Write the formula for the following compounds:
1. Magnesium iodide
2. Calcium sulfite
3. Barium hydrogen carbonate
4. Iron (III) phosphate