6.3 Naming Compounds and
Writing Formulas
Chapter 6
Chemical Bonds
What are we going to learn?
• How to write the name and formula of ionic and
covalently bonded compounds
Naming Ionic Compounds
• Ionic compound name: distinguishes the
compound from other ionic compounds
containing the same elements
• Name = words (ex: calcium chloride)
• Ionic compound formula: describes the ratio of
the ions in the compound
• Formula = numbers of elements (ex: CaCl2)
Binary Compounds
• If a compound is made from only two elements
is a binary compound
(Ex: salt is a binary compound made of sodium
and chlorine - sodium chloride)
What’s in a Name?
• To name a binary compound: list the name of
the cation (+ ion) followed by the name of the
anion (- ion)
Cations – First in Naming
• Cation: simply the name of the metal (no
changes)
• Ex: sodium atom and sodium ion
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This works for groups 1A, 2A and Aluminum
Group 1A has a 1+ charge
Group 2A has a 2+ charge
Aluminum (Group 3A) has a 3+ charge
• Transition metals with more than one possible
charge have a different naming strategy
• Name of the ion contains a Roman
numeral to indicate the charge
• Ex: copper (II) ion
Anions – The Followers
• Anion: use name of the nonmetal with the suffix
–ide replacing –ine
(ex: chlorine atom and chloride ion)
• Nonmetals are on the right side of the periodic
table
• Ex: sodium chloride
(cation) (anion)
Formulas
• If you know the name of an ionic compound,
you can write its chemical formula
• Chemical formula includes chemical symbols of
the elements and numbers (indicating amounts
of each element)
How do you write a formula?
• Write the symbol of the cation first
• Follow with the symbol of the anion
• Use subscripts to show the ratio of the ions in
the compound
Polyatomic Ions
• A covalently bonded group of atoms that has a
positive or negative charge and acts as a unit
• Ex: nitrate (NO)3-, sulfate (SO4)2-, phosphate
(PO4)3-
Molecular Compounds
• Name and formula of a molecular compound
describe the type and number of atoms in a
molecule of the compound
• These elements are usually on the right side of
the periodic table
• Elements in the compound share electrons
The molecules in the top row bond by sharing electrons.
The compounds in the bottom row join in polar covalent bonds.
Naming a Molecular Compound
• Most metallic element name appears first (most
left in the periodic table)
• Name of the second element is changed to end
in the suffix -ide
• Ex: carbon dioxide
• Prefixes indicate amount of atoms in the
molecule
• Ex: di shows that there are two carbon atoms in
the molecule
Molecular Formula
• Write the symbols for the elements in the order
the elements appear in the name
• Prefixes in the compound name indicate the
number of atoms of each element in the
molecule
• Prefixes appear as subscripts in the formula
Writing Chemical Formulas for
Binary Compounds Practice
• 1 - Write the symbols for the elements.
2 - Look up element ion charges and write them as
superscripts to the right of the elemental symbols.
3 - Use the correct combination of ions to produce a
compound with a net charge of zero. Multiple ions
are indicated with subscripts.
• lithium oxide
• potassium chloride
• calcium oxide
• barium bromide
Writing Chemical Formulas for
Binary Compounds Practice
• 1 - Write the symbols for the elements.
2 - Look up element ion charges and write them as
superscripts to the right of the elemental symbols.
3 - Use the correct combination of ions to produce a
compound with a net charge of zero. Multiple ions
are indicated with subscripts.
• lithium oxide Li2O
• potassium chloride KCl
• calcium oxide CaO
• barium bromide BaBr2
Writing Chemical Formulas for Binary
Compounds with Polyatomic Ions
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lithium carbonate
calcium nitrate
ammonium sulfide
sodium sulfate
Writing Chemical Formulas for Binary
Compounds with Polyatomic Ions
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lithium carbonate Li2CO3
calcium nitrate Ca(NO3) 2
ammonium sulfide (NH4) 2S
sodium sulfate Na2SO4
Writing Chemical Formulas for
Transition Metals Practice
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Lead (IV) carbonate
Copper (II) nitrate
Iron (III) oxide
Tin (IV) fluoride
Writing Chemical Formulas for
Transition Metals Practice
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Lead (IV) carbonate Pb(CO3)2
Copper (II) nitrate Cu(NO3)2
Iron (III) oxide Fe2O3
Tin (IV) fluoride SnF4
Writing Chemical Names for
Transition Metals Practice
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Fe(NO3)2
CuF2
NiS
FeCl2
Writing Chemical Names for
Transition Metals Practice
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Fe(NO3)2
CuF2
NiS
FeCl2
iron (II) nitrate
copper (II) fluoride
nickel (II) sulfide
iron (II) chloride
Writing Chemical Formulas Practice
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zinc carbonate
barium oxide
cadmium fluoride
magnesium sulfide
lithium phosphate
Writing Chemical Formulas Practice
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zinc carbonate
barium oxide
cadmium fluoride
magnesium sulfide
lithium phosphate
ZnCO3
BaO
CdF2
MgS
Li3PO4
Writing Chemical Names Practice
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FeF2
FeF3
Hg2Br2
HgBr2
Writing Chemical Names Practice
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FeF2
FeF3
Hg2Br2
HgBr2
iron (II) fluoride
iron (III)fluoride
mercury (I) bromide
mercury (II) bromide
Writing Chemical Names Practice
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BaSO4
FeF2
CuCO3
CaS
MgO
KCl
Writing Chemical Names Practice
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BaSO4
FeF2
CuCO3
CaS
MgO
KCl
barium sulfate
iron (II) fluoride
copper (II) carbonate
calcium sulfide
magnesium oxide
potassium chloride
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NO
N2O
NO2
N2O5
N2O3
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NO
N2O
NO2
N2O5
N2O3
nitrogen monoxide
dinitrogen monoxide
nitrogen dioxide
dinitrogen pentoxide
dinitrogen trioxide