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NAMING CHEMICAL
FORMULAS
Sodium Hydroxide
Potassium Chloride
Hydrochloric Acid
Iron (III) Chloride
Carbon Tetrachloride
Naming Ionic Compounds
METAL AND NONMETAL
• Write the metal name first
• Lithium
• Write the nonmetal name
• Oxygen
Li2O
last
• Change the ending of the word
to “ide”
• Oxide
Li2O = Lithium Oxide
Naming Ionic Compounds
POLYATOMICS
• Write the metal name first
• Lithium
• Write the polyatomic name
• Hydroxide
LiOH
LiOH = Lithium Hydroxide
Writing the Formula
Lithium Oxide
• Write the metal first with it’s oxidation number
• Li+
• Write the nonmetal second with it’s oxidation number
• O-2
• Criss-Cross to get Li2O
Li+ O-2
Li2O = Lithium Oxide
Transition Metals
Copper (II) Nitride
• The metal is listed first.
• The oxidation number is given
as a roman numeral number
and converted to a number.
• The nonmetal is written last
Cu
(II) is a +2, Cu+2
N-3
with its oxidation number.
• Criss-Cross to get Cu3N2
Cu+2 N-3
Naming With Transition Metals
Fe2O3
• Write the metal name first.
• Iron
• Add the oxidation number in
• Iron (III)
the form of a roman numeral
number.
• Write the nonmetal name
last
• Change the ending of
the element to “ide”
• Iron (III) Oxide
Finding the Oxidation Number of
a Transition Metal
• Charges must balance!!!!! This is the key!
Fe2O3
• Determine the oxidation number for the nonmetal
• O has a -2 oxidation number
• Determine how many oxygen there are in the formula
• Fe2O3 contains 3 oxygen atoms
• Multiply the number of oxygen atoms by the oxidation number
• 3 x -2 = -6 Therefore we have a total of 6 negative charges
• Determine the number of Irons you have
• Fe2O3 contains 2 Irons
• Divide the number of negative charges by the number of Irons
• 6÷2=3
• This is the positive oxidation number of the metal
• Fe has a +3 oxidation number
Naming Molecular Compounds
NONMETAL AND NONMETAL
• Prefixes are used to show the
number of atoms of each
element.
CO2
Carbon Dioxide
MonoDiTriTetraPentaHexa-
1
2
3
4
5
6
Naming Molecular Compounds
NONMETAL AND NONMETAL
• The least electronegative goes first.
• The ending of the second element is changed to “-
ide”.
S3Br5
S3 - The three is the prefix “tri” so
Trisulfur
Br5 - The five is the prefix “penta-” so
Trisulfur pentabromide
ACID – SINGLE ELEMENT
H2S
• Notice that the formula begins
with hydrogen, H, so this
means you end the name with
“acid”.
Hydrosulfuric acid
• Since it is just one element
other than hydrogen, you add
the prefix “hydro-”
• add the suffix “ic-” to the
second element.
ACIDS – POLYATOMIC ION
H2SO4 or H2SO3
• The word must end in “acid”
• If the polyatomic ion’s name
ends with “ite-”, then the
ending changes to “ous-”.
• If the polyatomic ion’s name
ends with “ate-”, then the
ending changes to “ic-”.
Sulfite
Sulfurous
Sulfate
Sulfuric
Sulfuric Acid
Sulfurous Acid
OVERALL RULES
First
Check to see what category the first element is in:
metal, transition metal, nonmetal
Second
Check the rules for the appropriate category
Third
BE CAREFUL with transition. They use roman
numeral numbers to name the oxidation number and
they can be reduced so uncross to check
Fourth
Ones, “1”, are understood - just as in math