Naming Binary Ionic Compounds
The first question you ask yourself “Is there a transition metal?”
If there are NO TRANSITION METALS:
Name to Formula
List the cation 1st, anion 2nd.
o Make sure that when writing name to formula, the oxidation numbers of the
formula add up to ZERO.
 You do this by using the CRISS CROSS method.
Write the oxidation number for each element.
Transfer the superscript oxidation number from the cation to the
subscript position in the anion.
Do the same with the anion’s oxidation number.
 After CRISS CROSSING, ignore the sign on the subscript
o If you were going to write in a 1, you just leave the 1 invisible
o The numbers DO matter in this case because the specific formula is important.
Ex:
Sodium Sulfide
Potassium chloride
= Na+1 S-2
= Na+1 S-2
= K+1 Cl-1
= Na2 S
= K+1 Cl-1
= KCl
Remember, the 1’s disappeared because we never put a one in the
subscript.
If there ARE TRANSITION METALS:
Name to Formula
List the cation 1st, anion 2nd.
o Make sure that when writing name to formula, the oxidation numbers of the
formula add up to ZERO.
o You do this by using the CRISS CROSS method.
 Write the oxidation number for each element. (The oxidation number of
the transition metal is the roman numeral in parenthesis)
 Transfer the superscript oxidation number from the cation to the
subscript position in the anion.
 Do the same with the anion’s oxidation number.
o After CRISS CROSSING, ignore the sign on the subscript
o If you were going to write in a 1, you just leave the 1 invisible
The numbers DO matter in this case because the specific formula is important.
Ex:
Zinc (III) Oxide
= Zn+3 O-2
= Zn+3 O-2
= Zn2O3
Copper (II) Oxide = Cu+2 O-2 = Cu+2 O-2 = CuO
Remember, the 2’s both simplified down to 1’s, and 1’s disappeared
because we never put a one in the subscript.
Name to Formula (NO transition metals)
1. sodium sulfide __________________________________
2. calcium bromide __________________________________
3. gallium chloride __________________________________
4. beryllium oxide _____________________________________
5. potassium nitride _____________________________________
Name to Formula (WITH transition metals)
6. zinc (III) selenide__________________________________
7. silver (II) iodide__________________________________
8. cobalt (II) bromide__________________________________
9. copper (II) oxide __________________________________
10.
copper (III) oxide __________________________________
Name to Formula (WITH transition metals)
11.
aluminum phosphide
Is there a transition metal?______
Write the Formula:_______________________
12.
iron (II) flouride
Is there a transition metal?______
Write the Formula:_______________________
13.
silver (II) nitride
Is there a transition metal?______
Write the Formula:_______________________
14.
calcium oxide
Is there a transition metal?______
Write the Formula:_______________________
15.
Potassium sulfide
Is there a transition metal?______
Write the Formula:_______________________
If there are NO TRANSITION METALS:
Formula to Name
List the cation 1st.
o The name of the cation is just the name of the element.
List the anion 2nd.
o The name of the anion is the name of the element with the ending
taking off and “-ide” added.
The numbers do not matter at all in this case.
Ex:
K2O = Potassium Oxide
LiF = Lithium Flouride
If there ARE TRANSITION METALS:
Formula to Name
List the cation 1st.
o The name of the cation is just the name of the element.
o Because the Cation is the transition metal, you need to include the
OXIDATION NUMBER of the cation by putting Roman Numerals in
parenthesis
 Do this by REVERSE CRISS CROSS
List the anion 2nd.
o The name of the anion is the name of the element with the ending
taking off and “-ide” added.
Ex:
Fe2O3
= Fe2O3
= Fe+3O-2
= Iron (III) Oxide
o The (III) in the parenthesis came from the 3 that was subscript next
to the Oxygen in the formula
TiS
= Ti S
= Ti+2S-2
= Titanium (II) sulfide
o We figured out the oxidation number of Titanium was +2 because Ti
and S were balanced. This meant knowing that S was -2, Ti had to be
+2.
Formula to Name (NO Transition Metals)
16.
K2O __________________________________
17.
NaF ___________________________________
18.
KI _____________________________________
19.
Mg3P2 _____________________________________
20.
Al2Se3 _____________________________________
Formula to Name (WITH Transition Metals)
21.
Ni2O __________________________________
22.
CrCl3 _____________________________________
23.
Cu S ___________________________________
24.
Mn3P2 _____________________________________
25. Au2Se _____________________________________
Formula to Name (some WITH Transition Metals, some WITHOUT)
26.
Rb3N
Is there a transition metal?______ Name the compound:_______________________
27.
Fe2O3
Is there a transition metal?______ Name the compound:_______________________
28.
CaCl2
Is there a transition metal?______ Name the compound:_______________________
29.
GaBr3
Is there a transition metal?______ Name the compound:_______________________
30.
Ag2O3
Is there a transition metal?______ Name the compound:_______________________