1. 9.1 Naming Ions >
Chapter 9
Chemical Names and Formulas
9.1 Naming Ions
9.2 Naming and Writing Formulas for
Ionic Compounds
9.3 Naming and Writing Formulas for
Molecular Compounds
9.4 Naming and Writing Formulas for
Acids and Bases
9.5 The Laws Governing How
Compounds Form
1
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2. 9.1 Naming Ions > Monatomic Ions
Ionic compounds consist of a positive metal ion
and a negative nonmetal ion combined in a
proportion such that their charges add up to a
net charge of zero.
• What is the formula of the compound
that will be made from Na and Cl?
2
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3. 9.1 Naming Ions > Monatomic Ions
It is important, in learning the language of
chemistry, to be able to name and write the
chemical formulas for all ionic compounds.
• The first step is to learn about the ions that
form ionic compounds.
• Some ions, called monatomic ions,
consist of a single atom with a positive or
negative charge resulting from the loss or
gain of one or more valence electrons,
respectively.
3
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4. 9.1 Naming Ions > Monatomic Ions
Cations
Recall that metallic elements tend to lose
valence electrons.
•What is the charge of the aluminum ion?
•What is the charge of the calcium ion?
4
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5. 9.1 Naming Ions > Monatomic Ions
Naming Cations
• The names of the cations of Group 1A,
Group 2A, and Group 3A metals are the
same as the name of the metal, followed
by the word ion or cation.
•
5
Thus, Na+ is the sodium ion (or cation),
Ca2+ is the calcium ion (or cation), and
Al3+ is the aluminum ion (or cation).
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6. 9.1 Naming Ions > Monatomic Ions
Anions
Nonmetals tend to gain electrons to form
anions, so the charge of a nonmetallic ion is
negative.
• What is the charge of the ion formed
from the phosphorus atom?
• What is the charge of the ion formed
from the fluorine atom?
6
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7. 9.1 Naming Ions > Monatomic Ions
Naming Anions
Anion names start with the stem of the
element name and end in -ide.
• For example, two elements in Group 7A
are fluorine and chlorine. The anions for
these nonmetals are the fluoride ion
(F–) and the chloride ion (Cl–).
7
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8. 9.1 Naming Ions >
Sample Problem 9.1
Naming Cations and Anions
Name the ion formed by each of
the following elements:
a. potassium
b. oxygen
c. sulfur
8
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9. 9.1 Naming Ions >
1
Sample Problem 9.1
Analyze Identify the relevant concepts.
You can use the periodic table to determine the
charge of most Group A elements.
•Ions with positive charges are cations;
• Metallic cations take the name of the
metal.
•Ions with negative charges are anions.
• The names of nonmetallic anions end in
-ide.
9
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10. 9.1 Naming Ions >
Sample Problem 9.1
2 Solve Apply concepts to the situation.
Write the symbol for the element.
a. K
b. O
c. S
10
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11. 9.1 Naming Ions >
Sample Problem 9.1
2 Solve Apply concepts to the situation.
Determine the charge of the ion formed by the
element.
a. K
b. Pb
4+
c. S
11
1+
2–
A negative charge
means electrons
gained; a positive
charge means
electrons lost.
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12. 9.1 Naming Ions >
Sample Problem 9.1
2 Solve Apply concepts to the situation.
Determine whether the ion is a cation or an
anion.
a. K
K+ is a cation.
b. O
2–
O2– is an anion.
c. S
12
1+
2–
S2– is an anion.
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13. 9.1 Naming Ions >
Sample Problem 9.1
2 Solve Apply concepts to the situation.
Apply the appropriate rules for naming the ion.
Use a Roman numeral if necessary.
a. Following the rules for naming metallic
cations, K+ is named potassium ion.
b. Following the rules for naming nonmetallic
anions, O2– is named oxide ion.
c. Following the rules for naming
nonmetallic anions, S2– is named sulfide
ion.
13
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14. 9.1 Naming Ions >
What type of elements (metals or
nonmetals) tends to form cations?
What type of elements tends to form
anions?
14
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15. 9.1 Naming Ions >
What type of elements (metals or
nonmetals) tends to form cations?
What type of elements tends to form
anions?
Metals tend to form cations.
Nonmetals tend to form anions.
15
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16. 9.1 Naming Ions >
CHEMISTRY & YOU
Suppose you were trying to teach someone
how to name ions. Which rules about the
“language of chemistry” would you
emphasize?
Answer this question at the top of INB102.
16
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17. 9.1 Naming Ions >
CHEMISTRY & YOU
Suppose you were trying to teach someone
how to name ions. Which rules about the
“language of chemistry” would you
emphasize?
• For cations, the word ion or cation follows the name of
the element.
• Metals that form more than one cation are named by
adding a Roman numeral in parentheses to indicate
the value of the charge after the name of the element,
followed by the word ion.
• Anion names start with the stem of the element name
and end in -ide.
17
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18. 9.1 Naming Ions >
Naming Compounds
Name the ionic compounds shown here.
a. MgCl2
b. Li3N
c. Al2S3
18
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19. 9.1 Naming Ions >
1
Sample Problem 9.1
Analyze Identify the relevant concepts.
You can use the periodic table to determine the
charge of most Group A elements.
•Ions with positive charges are cations;
• Metallic cations take the name of the
metal.
•Ions with negative charges are anions.
• The names of nonmetallic anions end in
-ide.
19
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20. 9.1 Naming Ions >
Sample Problem 9.1
2 Solve Apply concepts to the situation.
Write the name of the cations.
a. MgCl2
b. Li3N
lithium
c. Al2S3
20
magnesium
aluminum
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21. 9.1 Naming Ions >
Sample Problem 9.1
2 Solve Apply concepts to the situation.
Write the name of the anion.
a. MgCl2
magnesium chloride
b. Li3N
lithium nitride
c. Al2S3
aluminum sulfide
When naming ionic
compounds, ignore
the numbers in the
formula.
21
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