1. with modifications by Ken Costello
NOMENCLATURE
OF IONIC
COMPOUNDS
By John Weide
with modifications by Ken Costello

2. IONIC COMPOUNDS Metal Non-metal Oxygen-8 Magnesium-12
Compounds are two or more elements that are held together by opposite charge attraction.
IONIC COMPOUNDS
Oxygen-8
8 (+) 10 (-) -2 Charge
12 (+) 10 (-) +2 Charge
Magnesium-12
Metal
Non-metal

3. Metals Metals combine with non-metals
Metals loose electrons to non-metals
They then attract because their charges will be opposite.
Metals

4. Negative Ions (single atoms)-3 -2 -1
Most of the negative ions have a set negative charge

5. -1 +1 -2 +2 +3 -3 +1 +2

6. The next table contains the polyatomic
For example the oxy-salts of chlorine, bromine and iodine have many trends in common. Look for them below……
perchlorate ClO4-1
chlorate ClO3-1
chlorite ClO2-1
hypochlorite ClO-1
perbromate BrO4-1
bromate BrO3-1
bromite BrO2-1
hypobromite BrO-1
periodate IO4-1
iodate IO3-1
iodite IO2-1
hypoiodite IO-1
The next table contains the polyatomic
ions that need to be committed to memory. Remember to learn the name, formula and oxidation number

7. POLYATOMIC IONS (charged building blocks) Polyatomic ions are mostly made of two non-metals.
Ions with -1 charge
perbromate BrO4-1
bromate BrO3-1
bromite BrO2-1
hypobromite BrO-1
perchlorate ClO4-1
chlorate ClO3-1
chlorite ClO2-1
hypochlorite ClO-1
periodate IO4-1
iodate IO3-1
iodite IO2-1
hypoiodite IO-1
nitrate NO3-1
nitrite NO2-1
hydroxide OH-1
cyanide CN-1
acetate C2H3O2-1
Permanganate MnO4-1
bicarbonate HCO3-1
Ions with a -2 Charge
carbonate CO3-2
sulfate SO4-2
sulfite SO3-2
chromate CrO4-2
dichromate Cr2O7-2
oxalate C2O4-2
Ions with a -3 Charge
phosphate PO4-3
phosphite PO3-3
arsenate AsO4-3
Ions with +1 charge
ammonium ion NH4+1

8. -1 These polyatomic ions match the charge of the single element
Ions with -1 charge
perbromate BrO4-1
bromate BrO3-1
bromite BrO2-1
hypobromite BrO-1
perchlorate ClO4-1
chlorate ClO3-1
chlorite ClO2-1
hypochlorite ClO-1
periodate IO4-1
iodate IO3-1
iodite IO2-1
hypoiodite IO-1

9. -3 -2 These polyatomic ions match the charge of the single element
Ions with a -2 Charge
sulfate SO4-2 sulfite SO3-2
Ions with a -3 Charge
phosphate PO4-3
phosphite PO3-3 -3 -2

10. It is also important to memorize the oxidation of the ions that have fixed oxidation numbers (positive or negative). In particular, those from groups 1A, 2A, 3A, 4A, 5A, 6A, 7A, 8A and the elements: Zn, Cd and Ag. Use the following periodic chart to determine their oxidation numbers. Just click on the element symbol…

11. Elements with Fixed Oxidation Numbers +1 +2 +3 -4 -3 -2 -11A 7A 8A H H He 2A 3A 4A 5A 6A Li Be B C N O F Ne
Click on element to see its oxidation number(s) Na Mg Al Si P S Cl Ar K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe Ce Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn Fr Ra Ac Rf Db Sg Rh Hs Mt Nd Pm Sm Eu Gd Tb Ce Pr Yb Lu Dy Ho Er Tm Np Am Cm Bk Th Pa No Lr Cf Es Fm Md U Pu
Next Slide

12. Naming Ionic Compounds
The positive ion (usually a metal) is named first while the negative ion (a non-metal or a polyatomic ion) is named last.
The charge on the negative ion is used to determine the charge on the positive ion.
In-order for the total oxidation state to be zero, the total positive charge must equal the total negative charge. A simple algebraic equation can be used to determine the charge on a single metal ion.
This charge is expressed as a “Roman Numeral” in parenthesis that immediately follows the name of the metal.
CuSO4
Cu?SO4-2
x +(-2)=0
X = 2
Copper (II) Sulfate

13. Naming Ionic Compounds
The positive ion (usually a metal) is named first while the negative ion (a non-metal or a polyatomic ion) is named last.
The charge on the negative ion is used to determine the charge on the positive ion.
In-order for the total oxidation state to be zero, the total positive charge must equal the total negative charge. A simple algebraic equation can be used to determine the charge on a single metal ion.
This charge is expressed as a “Roman Numeral” in parenthesis that immediately follows the name of the metal.
Cu2SO4
Cu2+xSO4-2
2x +(-2)=0
x = 1
Copper (I) Sulfate

14. Naming Ionic Compounds
If the positive ion is one that has a fixed oxidation number then no Roman Numeral is used.
Everyone should know the charge of fixed ions. These include metals in group 1A, 2A and the specific metals: Al, Zn, Cd & Ag (zinc, cadmium and silver).
CaSO4
Calcium Sulfate
No Roman Numeral

15. If the ionic compound is binary it will end in “-ide”
If the ionic compound is binary it will end in “-ide”. However, not all compounds that end in “-ide” are binary. For example sodium hydroxide has the formula…NaOH (three different kinds of atoms).
If the negative ion is a polyatomic ion the compound is no longer binary. The ending will be that carried by the polyatomic ion. These endings are either “-ate” or “-ite.”
Hydrated compounds are named using a combination of both the stock system and prefixes. A prefix is used to denote the number of water molecules attached to the ionic formula. “hydrate” is used as the name indicating that water is attached. For example, copper(II) sulfate pentahydrate has the formula CuSO4.5H2O

16. Examples #1- Formulas to Names
1. Write the names of the ions
CuSO3 -2
= 0
2. Determine the charge of the positive ion Cu +2
SO3 x
X + (- 2) = 0
I’m a polyatomic ion
The sum of the positive and negative charges must equal zero
You must know the charge on the sulfite ion is -2
X = +2
copper
sulfite
(II)
Final Name
Next

17. Examples #2- Formulas to Names
1. Write the names of the ions
I’m a polyatomic ion
KMnO4
potassium
permanganate
Final Name
If the positive ion has a fixed charge, you are finished.

18. Examples #3- Formulas to Names
1. Write the names of the ions
2. Determine the charge of the positive ion
I’m a polyatomic ion
NH4NO3
ammonium
nitrate
Final Name
If the positive ion has a fixed charge, you are finished.

19. Examples #4- Formulas to Names
1. Write the names of the ions
2. Determine the charge of the positive ion
X = +2
X + 2(-1) = 0
Snx (F-1)2 = 0
SnF2
tin
fluoride
(II)
Final Name

20. Examples #5- Formulas to Names
1. Write the names of the ions
2. Determine the charge of the positive ion
I’m a polyatomic ion
Ba(ClO4)2
barium
perchlorate
If the positive ion has a fixed charge, you are finished.
Final Name

21. Examples #6- Formulas to Names
1. Write the names of the ions
2. Determine the charge of the positive ion
X = +1
2X + (-2) = 0
2Cux (S)-2 = 0
I’m not a polyatomic ion
Cu2S
copper
sulfide
(I)
Final Name

22. Examples #6- Formulas to Names
1. Write the names of the ions
Cu2S -2
2. Determine the charge of the positive ion
(Cu )2 +1 S x
2X + (- 2) = 0
The sum of the positive and negative charges must equal zero
You must know the charge on the sulfide ion is -2
2X = +2
X = +1
copper
(I)
sulfide
Final Name
Next

23. Examples #7- Formulas to Names
1. Write the names of the ions
2. Determine the charge of the positive ion
X = +1
2X + (-2) = 0
2(Nax)(Cr2O7)-2 = 0
I’m a polyatomic ion
Na2Cr2O7
sodium
dichromate
(I)
If the positive ion has a fixed charge, it is not shown
Final Name

24. Examples #10- Formulas to Names
1. Write the names of the ions
2. Determine the charge of the positive ion
I’m a polyatomic ion
LiCN
lithium
cyanide
If the positive ion has a fixed charge, you are finished.
Final Name

25. Writing Ionic Formulas
It is easier to write the formula of an ionic compound from its name than the reverse.
The oxidation number of the negative ion must be memorized in all cases. Refer to the table of polyatomic ions.

26. Example #1-Names to Formulas
1. Write symbols of elements
2. Determine number of ions
(Al )x(Cl-1)y= 0 +3
What is the Lowest Common Multiple “LCM” of 3 and 1. Do not worry about the sign(+/-)
aluminum chloride
If there is no Roman Numeral, you need to know the fixed oxidation number of the positive ion. Al Cl 1 3
If there is only one atom the “1” is not shown
Final Formula
Next

27. Example #1-Names to Formulas
aluminum chloride
1. Write symbols of elements
2. Determine number of ions
(Al )x(Cl-1)y +3
If there is no Roman Numeral, you must know the oxidation number of the positive ion.
If there is no Roman Numeral, you must know the oxidation number of the positive ion.
What is the Lowest Common Multiple “LCM” of 3 and 1. Do not worry about the sign(+/-)
What is the Lowest Common Multiple “LCM” of 3 and 1. Do not worry about the sign(+/-)
For aluminum,
a 1 is multiplied
times the +3 to give
a +3 charge
Remember all compounds
are neutral, thus
the total positive charge
must equal the
total negative charge
For chloride,
a 3 is multiplied
times the -1 to give
a -3 charge
This formula says that
the +3 charge of one Al
atom will cancel the-3
charge from 3 Cl atoms
x(+3) + y(-1) = 0
1(+3) + 3(-1) = 0 Al Cl 1 3
If there is only one atom the “1” is not shown
Final Formula
Next

28. 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
Next

29. Example #3-Names to Formulas
Y 3 =
1. Write symbols of elements
3X = 1y
X(+3) + y(-1) = 0
2. Determine number of ions
(Ni+3)x(C2H3O2-1)y= 0
nickel(III) acetate
Choose the lowest set of integers that satisfies the equation Ni
(C2H3O2)3
C2H3O2 1
If there is only one atom the “1” is not shown
Final Formula
Next

30. Example #4-Names to Formulas
Y 1 =
1. Write symbols of elements
1X = 3y
X(+1) + y(-3) = 0
2. Determine number of ions
(Li )x(PO4-3)y= 0 +1
lithium phosphate
If there is no Roman Numeral, you need to know the fixed oxidation number of the positive ion.
If there is no Roman Numeral, you need to know the fixed oxidation number of the positive ion.
Choose the lowest set of integers that satisfies the equation Li
(PO4)1
PO4 3
If there is only one atom the “1” is not shown
Final Formula
Next

31. Practice Problems
By now you should have an idea of what is expected when naming covalent binary compounds using prefixes.
In order to master this naming system you need to practice until you feel proficient in naming compounds using prefixes.

32. Practice Problem #1 No, you do not use prefixes
Fe(NO3)3
Choose the correct name for the compound
1. Iron trinitrate
No, you do not use prefixes
2. iron(I) nitrate
No, you have the wrong oxidation number
3. iron(III) nitrite
No, you need to review polyatomic ions
4. iron(III) nitrate
Very good, click arrow to continue
5. none of the above
No, there is a correct answer
next problem
Periodic Chart
Polyatomic Ions

33. Practice Problem #2 No, you need to review prefixes
sodium chlorite
Choose the correct formula for the compound
1. NaCl
No, you need to review prefixes
2. NaClO
No, you need to review prefixes
3. NaClO2
Very good, click arrow to continue
4. Na(ClO)2
No, you have several errors
5. none of the above
No, there is a correct answer
next problem
Periodic Chart
Prefixes

34. POLYATOMIC IONS return Ions with -1 charge perbromate BrO4-1
bromite BrO2-1
hypobromite BrO-1
perchlorate ClO4-1
chlorate ClO3-1
chlorite ClO2-1
hypochlorite ClO-1
periodate IO4-1
iodate IO3-1
iodite IO2-1
hypoiodite IO-1
nitrate NO3-1
nitrite NO2-1
hydroxide OH-1
cyanide CN-1
thiocyanate SCN-1
acetate C2H3O2-1
Permanganate MnO4-1
bicarbonate HCO3-1
Ions with a -2 Charge
carbonate CO3-2
phthalate C8H4O4-2
sulfate SO4-2
sulfite SO3-2
chromate CrO4-2
dichromate Cr2O7-2
oxalate C2O4-2
peroxide O2-2
Ions with a -3 Charge
phosphate PO4-3
phosphite PO3-3
arsenate AsO4-3
Ions with +1 charge
ammonium ion NH4+1
return

35. Click on element to see its oxidation number(s)
Oxidation Numbers (most common) -3 -2 +2 +1 -1 +3 -4 +1 +2 +2 +3 +2 +4 1A 7A 8A H H He 2A 3A 4A 5A 6A Li Be B C N O F Ne
Click on element to see its oxidation number(s) Na Mg Al Si P S Cl Ar K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe Ce Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn Fr Ra Ac Rf Db Sg Rh Hs Mt Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
return Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr