Naming Compounds
*Binomial Nomenclature
Two types of chemical
compounds you will name:
 Binary
Ionic:
Metal and a nonmetal
We will not be using transition
metals!
Binary
AKA:
Molecular: Two nonmetals
Covalent compounds
REMINDER:
 Metals:
Are found to the LEFT of the
stair-step line
Remember,
 Nonmetals:
Hydrogen is a nonmetal
Are found to the RIGHT of
the stair-step line
 Transition Metals: Found in the “dip”
or middle of the periodic table
4
NAMING BINARY IONIC
COMPOUNDS
 When
naming, metals ALWAYS come before
the nonmetal
Name
the first element as is
Name
the second element ending in
“ide”
EXAMPLES
 NaCl
sodium chloride
 CaO
calcium oxide
 Al2S3
 MgI2
aluminum sulfide
magnesium iodide
NAMING BINARY MOLECULAR
 These
compound contain two elements
(binary)
 The term molecular indicates that
these elements are joined by a
covalent bond
Two
nonmetals
Common Prefixes for Covalent Bonds
 Prefixes
are used to tell the number of
atoms of each element in a molecule
Prefix
Number
mono
di
tri
tetra
penta
hexa
hepta
octa
nona
deca
1
2
3
4
5
6
7
8
9
10
Naming Covalent Bonds
 You
will use the prefixes to name
covalent bonds
Exception:
DO NOT use mono before
the first element if there is only one
WRONG:
CO- monocarbon monoxide
CORRECT:
Change
CO- carbon monoxide
the ending of the second
element to “ide”
EXAMPLES
 CO2
 CO
 N2O4
 CCl4
Carbon dioxide
Carbon monoxide
Dinitrogen tetraoxide
Carbon tetrachloride
WRITING FORMULAS FOR IONIC
COMPOUNDS
List the symbol for each ion and its charge
1.
Ie Al3+ F-

Find the least common multiple of the
ion’s charges to make the compound
Neutral
2.
Least common multiple of 3 and 1 is 3


You need 1 Al and 3 F
Write the formula with subscripts
3.

AlF3
IONIC FORMULAS CRISS-CROSS
METHOD
Write the ions
2. Cross the charges down
3. Drop the charges
4. Reduce if necessary
1.
EXAMPLES
 Lithium
Oxide
 Potassium
 Barium
Chloride
Bromide
Li2O
KCl
BaBr2
FORMULAS FOR MOLECULAR
COMPOUNDS
1.
2.
Write the symbols for the first and
second element
Translate the prefixes into subscripts
EXAMPLES
 Diarsenic
pentoxide
As2O5
 Tetraphosphorus
trisulfide
P4S3
 Tetraphosphorus
decoxide
P4O10
 Phosphorus
trichloride
PCl3