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The following flow chart is useful when you are naming binary ionic compounds:
Does the compound
contain Type I or
Type II cations?
Type I
Name the cation,
using the
element name.
Type II
Using the principle
of charge balance,
determine the
cation charge.
Include in the cation
name a Roman
numeral indicating
the charge.
CHEMISTRY in ACTION
Name Game I: Ionic Compounds
1. Make two sets of flashcards with names of ions on one side and symbol and charge on the other:
Set 1: all of the alkali and alkaline earth metals, plus iron(II) and
iron(III)
Set 2: all of the nonmetals from Groups 5, 6, and 7
2. Randomly pick one card from set 1, and one card from set 2. Write
the proper formula for the ionic compound made from these two ions,
and name the compound.
3. Repeat the previous step until you correctly name ten compounds in
a row. Make sure you can write formulas and names starting with either the names or the symbols and charges of the ions.
Naming Binary Compounds That Contain
Only Nonmetals (Type III)
Objective: To learn how to name binary compounds containing only
nonmetals.
B
inary compounds that contain only nonmetals are named in accordance
with a system similar in some ways to the rules for naming binary ionic
compounds, but there are important differences. Type III binary compounds
contain only nonmetals. The following rules cover the naming of these compounds.
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Chapter 4 Nomenclature
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TABLE 4.3
Prefixes Used to
Indicate Numbers in
Chemical Names
Prefix
Number
Indicated
monoditritetrapentahexaheptaocta-
1
2
3
4
5
6
7
8
Rules for Naming Type III Binary Compounds
1. The first element in the formula is named first, and the full element
name is used.
2. The second element is named as though it were an anion.
3. Prefixes are used to denote the numbers of atoms present. These prefixes are given in Table 4.3.
4. The prefix mono- is never used for naming the first element. For example, CO is called carbon monoxide, not monocarbon monoxide.
We will illustrate the application of these rules in Example 4.4.
Example 4.4
Naming Type III Binary Compounds
Name the following binary compounds, which contain two nonmetals
(Type III).
a. BF3
b. NO
c. N2O5
Solution
a. BF3
Rule 1 Name the first element, using the full element name: boron.
Rule 2 Name the second element as though it were an anion: fluoride.
Rules 3 and 4 Use prefixes to denote numbers of atoms. One boron
atom: do not use mono- in first position. Three fluorine atoms: use
the prefix tri-.
The name of BF3 is boron trifluoride.
b. Compound
NO
Individual Names
Prefixes
Comments
nitrogen
oxide
none
mono-
Mono- is not used
for the first
element.
The name for NO is nitrogen monoxide. Note that the second o in
mono- has been dropped for easier pronunciation. The common name
for NO, which is often used by chemists, is nitric oxide.
c. Compound
N2O5
Individual Names
Prefixes
Comments
nitrogen
oxide
dipenta-
two N atoms
five O atoms
The name for N2O5 is dinitrogen pentoxide. The a in penta- has been
dropped for easier pronunciation.
Self-Check Exercise 4.3
Name the following compounds.
a. CCl4
b. NO2
c. IF5
4.2 Naming Binary Compounds That Contain Only Nonmetals (Type III)
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A piece of copper metal about
to be placed in nitric acid (left).
Copper reacts with nitric acid to
produce colorless NO, which
immediately reacts with the oxygen in the air to form reddishbrown NO2 gas (right).
CHEMISTRY
Water and ammonia are always
referred to by their common
names.
The previous examples illustrate that, to avoid awkward pronunciation,
we often drop the final o or a of the prefix when the second element is oxygen. For example, N2O4 is called dinitrogen tetroxide, not dinitrogen tetraoxide, and CO is called carbon monoxide, not carbon monooxide.
Some compounds are always referred to by their common names. The
two best examples are water and ammonia. The systematic names for H2O
and NH3 are never used.
Nitric Oxide (NO)
U
ntil recently nitric oxide (NO, more correctly
called nitrogen monoxide) was primarily viewed
as an air pollutant. In the last few years, however,
NO has been found to be a potent biological regulator. It turns out that this compound is produced
in the body and regulates blood pressure by dilating blood vessels. Studies in the 1990s indicated
that NO administered to patients with sickle-cell
anemia may relieve serious symptoms of that disease. For example, it seems to benefit patients with
acute chest syndrome—characterized by chest pain,
fever, and high blood pressure in the lungs due to
clogged blood vessels—which is the most lifethreatening complication of sickle-cell disease, especially for children.
Sickle-cell anemia is a genetic disease that most
often strikes people of West African descent. It
causes the red blood cells to be misshapen (“sickle
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Chapter 4 Nomenclature
shaped”), which in turn causes them to stick together and block blood flow. NO is thought to bind
to a special site on the hemoglobin molecule (the
molecule that carries O2 from the lungs to the
tissues). It is released when blood
flow is impaired, causing dilation (expansion) of the
blood vessels, thus helping to improve blood
flow.
Further tests are
now under way to try
to discover exactly how
NO works to relieve
sickle-cell symptoms.
A mixture of normal and
sickle-shaped red blood