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Naming Binary Ionic
Compounds
• The positive ion (cation) is written first.
ƒ Takes the same name as the element.
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Nomenclature 2.1
• The negative ion (anion) is written last.
ƒ Takes the first part of its elements name,
and –ide is added to the end.
Ex) Bromine is changed to Bromide.
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Naming Ionic Compounds
Writing Ionic Formulas
Naming Hydrates
Naming Binary Ionic
Compounds
Ex) CuBr is written as Copper (I) Bromide.
• Bromide has to be Br1• Copper must be Cu1+ to make the compound neutral.
Ex) Fe2O3 is written as Iron (III) Oxide.
•
•
•
•
Oxide has to be O2As there are three of them, they make up a charge of 6The two irons must combine to form a charge of 6+
Thus, each iron must carry a charge of 3+
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• You need to know if an element forms cations
with different charges.
• If it does, you need to specify the charge in
Roman numerals.
• Ex) CuS is written as Copper(II) Sulfide
• Sulfide has to be S2• Copper must be Cu2+ to make the compound
neutral
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Naming Binary Ionic
Compounds
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Naming Binary Ionic
Compounds
LiF
CaBr2
K2S
FeS
MgO
MnO
CoI3
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1)
2)
3)
4)
5)
6)
7)
Naming Compounds with
Polyatomic Ions
• For polyatomic ions, always use the name assigned
to it.
– Do not add an additional suffix (such as –ide).
e.g.) CO32- is the carbonate ion.
CaCO3 is calcium carbonate
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Naming Compounds with
Polyatomic Ions
Hints for Learning the Names of
Polyatomic Ions
• Ammonium, NH4+, is the only polyatomic cation
that you need to know.
• Only three polyatomic ions end in –ide.
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e.g.) NH4Cl is ammonium chloride
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ƒ CN- Cyanide
ƒ OH- Hydroxide
ƒ O22- Peroxide
e.g.) NO3- is the nitrate ion
NH4NO3 is ammonium nitrate
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Everything else ending in –ide is a monoatomic
anion.
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• A system for oxoanions.
ƒ Hypo-____-ite (2 less oxygens than ___-ate)
ƒ _____-ite
(1 less oxygen than ___-ate)
ƒ _____-ate
ƒ Per-____-ate
(1 more oxygen then ___-ate)
Hints for Learning the Names of
Polyatomic Ions
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Hints for Learning the Names of
Polyatomic Ions
• The example of Chlorate, ClO3ƒ
ƒ
ƒ
ƒ
Hypochlorite
Chlorite
Chlorate
Perchlorate
ClO- (2 less oxygens than __-ate)
ClO2- (1 less oxygen than __-ate)
ClO3ClO4- (1 more oxygen then__-ate)
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ƒ All polyatomic ions in such a series carry the
same charge.
• A system for oxoanions.
Naming Compounds with
Polyatomic Ions
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Hints for Learning the Names of
Polyatomic Ions
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• A system for oxoanions.
• The example of Sulfate (SO42-)
ƒ Sulfite
ƒ Sulfate
SO32- (1 less oxygen than __-ate)
SO42-
ƒ There is no hypo-___-ite or per-___-ate for sulfate.
1)
2)
3)
4)
5)
6)
7)
8)
CuCO3
K2SO3
Ca(ClO)2
KClO4
NaClO3
LiNO2
LiNO3
NaCH3COO
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Recognizing Ionic Compounds
Writing Ionic Formulas
• Ionic compounds are neutral.
– Thus, all charges must sum up to zero.
• Ionic compounds contain either a metal and a
non-metal, or polyatomic ions.
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• Charges come from the associated group in the
periodic table, or a list.
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• If the first word in the compound is a metal or
ammonium, it is an ionic compound.
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• Parenthesis must be used when there is some
multiple of a certain polyatomic ion.
Ex1) Writing Ionic Formulas
Ex1) Calcium Chloride
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Ex1) Writing Ionic Formulas
Criss-Cross Method
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• -ide in chloride tells you it is monoatomic
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• Calcium is always 2+ (Group 2A periodic table)
Ca2+ Cl1CaCl2
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• Chloride is always 1- (Group 7A periodic table)
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Ex2) Writing Ionic Formulas
Ex2) Writing Ionic Formulas
Ex 2) Iron (III) Sulfate
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Criss-Cross Method
• The Iron ion carries a charge of 3+, as the
Roman numeral is (III).
• You know that Sulfate is SO42- because you
memorized the table of polyatomic ions.
Fe3+ SO42Fe2(SO4)3
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Hydrates
Writing Ionic Formulas
• Hydrates are ionic compounds that trap water
within their structures.
Aluminum hydrogen sulfate
Iron (II) oxide
Iron (III) oxide
Strontium chromate
Potassium chloride
Ammonium Nitrate
Lithium Sulfite
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• Both the name and the chemical formula specify
how much water is contained within the
structure.
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1)
2)
3)
4)
5)
6)
7)
Writing Formulas for Hydrates
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e.g.) Sodium sulfate decahydrate
Na2SO4 • 10 H2O
2) FeCl3•6 H2O
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• Add a dot and the correct number of waters
taken from the prefix.
1) Barium Chloride Dihydrate
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• Write the formula for the ionic compound using
the rules you learned earlier.
Writing Formulas for Hydrates
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