Ch. 15 and 6 Naming and Writing
Formulas for Ionic Compounds
Writing Formulas for Binary Ionic Compounds
Ch. 6
A. Formula Unit:
the lowest whole-number ratio of ions in an
ionic compound
Writing Formulas for Binary Ionic
Compounds
B. Rules:
1. Write symbol and charge for both cation and
anion.
2. Crisscross the numbers for the charges and
write as subscripts.
3. CHECK!! The formula must be in the lowest
possible ratio of ions (this means reduce).
The cation is always written first!
practice problems
Write formulas for these compounds:
A. calcium iodide
+2
Ca 1
I
CaI2
2
B. Aluminum sulfide
+3
Al 2
-2
S
Al2S3
3
C. Tin (IV) oxide
+4
Sn 2
O
-2
4
Sn2O4 SnO2
D. Beryllium Oxide
+2
Be2
-2
O2
Be2O2 BeO
Naming Binary Ionic Compounds
1.) Name the cation.
Use Roman Numerals if Transition Metal.
(Middle Name, a roman numeral)
2.) Name the anion.
Drop their last names ending, put –ide in its place
NaCl
Sodium Ion
Chlorine Ion
Sodium Chloride
Naming Binary Ionic Compounds that
contain a transition metal
• Use Roman numerals (middle name) to show the
charge of the ion. Many of these elements can
form more than one ion:
Cr2+ Chromium II
or Cr3+ Chromium III
Cu+ Copper I
or Cu2+ Copper II
Mn2+ Manganese II or Mn3+ Manganese III
Fe2+ Iron II or
Fe3+ Iron III
Co2+ Cobalt II or Co3+ Cobalt III
Sn2+ Tin II or
Sn4+ Tin IV
Pb2+ Lead II or Pb4+ Lead IV
Zn1+ Zinc I or
Zn2+ Zinc II
Ni2+ Nickel II
or
Ni3+ Nickel III
Naming Binary Ionic Compounds
-2
SnS2
Find Sn
Where is it located?
Use Middle Name
Tin (IV) Sulfide
practice problems
A.) KCl
Potassium chloride
B.) CuBr2
Copper (II) bromide
C.) AlF3
Aluminum fluoride
D.) MgO
Magnesium oxide
E.) MnI2
Manganese (II) iodide
F.) ZnS
zinc (II) sulfide
Practice Problems
Show Understanding by SHOWING YOUR WORK
1.)
+
Na
Cl
NaCl
Sodium chloride
2.)
+
K
-2
S
K2S
Potassium sulfide
3.)
+3
Al
I
AlI3
Aluminum iodide
4.)
+
Ag
-2
O
Ag2O
Silver (I) oxide
5.)
+2
Ni
-2
O
Ni2O2 NiO
Nickel (II) oxide
+4
6.) Pb
-2
O
Pb2O4 PbO2
Lead (IV) oxide
Ionic Review
Write formulas for these binary ionic compounds
a. Barium Sulfide
BaS
SnCl4
b. Tin (IV) Chloride
Mg3N2
c. Magnesium Nitride
d. Sodium Oxide
Na2O
Review (cont.)
Name these binary ionic compounds:
a. KCl
Potassium chloride
Barium oxide
b. BaO
Copper (II) bromide
c. CuBr2
Iron (II) sulfide
d. FeS