1. Old System

2. The old naming system was one of the first methods of naming ionic compounds where the positive metal ion had two possible oxidation states. The “old method” was replaced by the much easier to use “stock system”. Chemical names are sometimes expressed in this old format. One should at least be able to recognize these old names when they are encountered, BUT the “Stock System” should be used when naming a compound.

3. The difficulty arises with the names and oxidation numbers of the positive metal ion
in the compound name.
Typically, for the name of the metal the old root word from whence the symbol of the metal was derived. For example, the original name for iron (symbol Fe) was ferrum.
The two positive oxidation numbers of the different metal ions have different values. For example, iron has oxidation numbers of +2 and +3 while lead has oxidation numbers of +2 and +4.

4. The oxidation number the positive ion is characterized by the ending of the name of the positive ion. If the name ends in –ous then the ion has the lowest value of the two positive charges and if it ends in –ic it has the highest of the two charges.
For example:
ferrous chloride iron has a +2 charge FeCl2
iron(II) chloride (Stock System)
ferric chloride iron has a +3 charge FeCl3
iron(III) chloride (Stock System)

5. Ferry boat to CoNi island @ 2 or 3.
Fe (ferrum) iron +2/+3
Co cobalt +2/+3
Ni nickel +2/+3
Mnemonic Device
Ferry boat to CoNi 2 or 3.
ferrous chloride Fe+2 FeCl2
ferric chloride Fe+3 FeCl3
cobaltous bromide Co+2 CoBr2
cobaltic bromide Co+3 CoBr3
nickelous sulfide Ni+2 NiS
nickelic sulfide Ni+3 Ni2S3

6. Man Sitten in the Pub @2 or 4
Mn manganese /+4
Sn (stannum) tin +2/+4
Pb (plumbum) lead +2/+4
Mnemonic Device
Man Sitten in the or 4
manganous nitrate Mn+2 Mn(NO3)2
manganic nitrate Mn+4 Mn(NO3)4
stannous fluoride Sn+2 SnF2
stannic fluoride Sn+4 SnF4
plumbous sulfate Pb+2 PbSO4
plumbic sulfate Pb+4 Pb(SO4)2

7. No Hugging of the Cuties @1 or 2
N nitrogen +1/+2
Hg mercury +1/+2
Cu copper cuprum +1/+2
Mnemonic Device
No Hugging of the or 2
nitrous oxide N+1 N2O
nitric oxide N+2 NO
mercurous carbonate Hg+1 Hg2CO3
mercuric carbonate Hg+2 HgCO3
cuprous nitride Cu+1 Cu3N
cupric nitride Cu+2 Cu3N2

8. REMEMBER
The only reason for this study of the old system is so that you can easily recognize this naming scheme. You should always use the stock system when writing the names of chemical compounds

9. Example #1-Names to Formulas
ferric phosphate
1. Write symbols of elements.
2. What are the oxidation numbers?
Fe PO4
? ? +3 -3
3. Determine number of ions. Fe +1 -1
PO4
Remember all compounds
are neutral, thus
the total positive charge
must equal the
total negative charge
This is the old naming system where the name ferric is derived from the root word ferrum which is the old name for iron.
You must also remember that the polyatomic ion (PO4) has a -3 oxidation number
This is the old naming system and the –ic ending of ferrum gives Fe a +3 oxidation number. Fe
PO4
Final Formula
Next

10. Example #2-Names to Formulas
manganous oxide
1. Write symbols of elements.
2. What are the oxidation numbers?
Mn O
? ? +2 -2
3. Determine number of ions. +1 Mn -1 O
Remember all compounds
are neutral, thus
the total positive charge
must equal the
total negative charge
You must also remember that oxygen has a -2 oxidation number
This is the old naming system where the name manganous is derived from the root word manganese
This is the old naming system and the –ous ending of manganous (manganese) gives Mn a +2 oxidation number. Mn O
Final Formula
Next

12. Cl -1 +1 Na -1 S +1 Ca Mn +1 Al +1 -1 N

13. Practice Problem #2 No, this is the formula for the -ic ending
nitrous oxide
Choose the correct formula for the compound
1. NO
No, this is the formula for the -ic ending
2. NO2
No, this example does not follow Old System
3. N2O
Very good, click arrow to continue
4. N2O2
No, this compound has too many oxygen atoms
5. none of the above
No, there is a correct answer
next problem
Element List
Old Names

16. Example #1-Names to Formulas
This is the old naming system
ferric phosphate
1. Write symbols of elements
2. Write number of atoms Fe
PO4
If no prefix, then 1 is implied and not written
Final Formula

17. Example #1-Names to Formulas
I’m a Binary Compound
Sulfur trioxide
1. Write symbols of elements S O 1 3
2. Write number of atoms
If no prefix, then 1 is implied and not written
Final Formula

18. Example #1-Names to Formulas
I’m a Binary Compound
Sulfur trioxide
1. Write symbols of elements S O 1 3
2. Write number of atoms
If no prefix, then 1 is implied and not written
Final Formula

19. Practice Problem #2 Very good, click arrow to continue
arsenic pentabromide
Choose the correct formula for the compound
1. AsBr5
Very good, click arrow to continue
2. ArBr5
No, "Ar" is not correct, see element list
3. AsBr7
No, you need to review prefixes
4. As5Br
No, the subscript is with the wrong element
5. none of the above
No, there is a correct answer
next problem
Element List
Prefixes

20. Example #1-Names to Formulas
aluminum chloride
1. Write symbols of elements.
2. What are the oxidation numbers?
Al Cl
? ? +3 -1
3. Determine number of ions. Al +1 Cl -1 3
Remember all compounds
are neutral, thus
the total positive charge
must equal the
total negative charge
If there is no Roman Numeral, you must know the oxidation number of the positive ion. Cl -1
You must also remember that chlorine is found in group 7A, which always has a minus one charge.
How many chlorine ions would be needed to
balance the +3 charge on the aluminum ion? Cl -1
If there is only one atom the “1” is not shown Al Cl 1 3
Final Formula
Next

21. Example #1-Names to Formulas
aluminum chloride
1. Write symbols of elements.
2. What are the oxidation numbers?
Al Cl
? ? +3 -1
3. Determine number of ions. Al +1 Cl -1 3
Remember all compounds
are neutral, thus
the total positive charge
must equal the
total negative charge
If there is no Roman Numeral, you must know the oxidation number of the positive ion. Cl -1
You must also remember that chlorine is found in group 7A, which always has a minus one charge.
How many chlorine ions would be needed to
balance the +3 charge on the aluminum ion? Cl -1
If there is only one atom the “1” is not shown Al Cl 1 3
Final Formula
Next

22. Example #2-Names to Formulas
Y 2 =
1. Write symbols of elements
2X = 1y
X(+2) + y(-1) = 0
2. Determine number of ions
(Co+2)x(BrO3-1)y= 0
cobalt(II) bromate
Choose the lowest set of integers that satisfies the equation Co
BrO3
(BrO3)2 1
If there is only one atom the “1” is not shown
Final Formula