1. Chapter 7 Chemical Formulas & Chemical Compounds
7.1 Chemical Names & Formulas

2. Ions
Cation: A positive ion
Mg2+, NH4+
Anion: A negative ion
Cl-, SO42-
Ionic Bonding: Force of attraction between oppositely charged ions.

3. Predicting Ionic Charges
Groups :
Many transition elements have more than one possible oxidation state.
Iron (II) = Fe2+
Iron (III) = Fe3+

4. Predicting Ionic Charges
Groups :
Some transition elements have only one possible oxidation state.
Zinc = Zn2+
Silver = Ag1+

5. Formula Writing for Binary Ionic Compounds
criss-cross the oxidation numbers to balance out the charge.
Magnesium Bromide
Mg Br – 1
Mg1Br2
MgBr2
Calcium Sulfide
Ca + 2 S – 2
Ca2S2
CaS

6. Writing Ionic Compound Formulas
Example: Iron (III) chloride
1. Write the formulas for the cation and anion, including CHARGES!
Fe3+
Cl-
2. Check to see if charges are balanced. 3
3. Balance charges, if necessary, using subscripts.
Not balanced!

7. Naming Ionic Compounds
1. Cation first, then anion
2. Monatomic cation = name of the element
Ca2+ = calcium ion
3. Monatomic anion = root + -ide
Cl- = chloride
CaCl2 = calcium chloride

8. Naming Ionic Compounds
Metals with multiple oxidation states
some metal forms more than one cation
use Roman numeral in name
PbCl2
Pb2+ is cation
PbCl2 = lead (II) chloride

9. Elements with Multiple Oxidation Numbers
Manganese II Mn+2
Manganese III Mn+3
Manganese VII Mn+7
Cobalt II Co+2
Cobalt III Co+3
Gold I Au+1
Gold III Au+3
Nickel II Ni+2
Nickel III Ni+3
Nickel IV Ni+4
**Silver Ag+1
**Zinc Zn+2
**Cadmium Cd+2
Copper I Cu+1 Copper II Cu+2 Iron II Fe+2 Iron III Fe+3 Mercury I Hg+1 Mercury II Hg+2 Lead II Pb+2 Lead IV Pb+4 Tin II Sn+2 Tin IV Sn+4 Chromium II Cr+2 Chromium III Cr+3 Chromium VI Cr+6

10. Name Formula Name Formula
Acetate
C2H3O2-1 (CH3COO -1)
Hypochlorite
ClO-1
Dichromate
Cr2O7-2
Chlorite
ClO2-1
Ammonium
NH4+1
Chlorate
ClO3-1
Nitrate
NO3-1
Perchlorate
ClO4-1
Nitrite
NO2-1
Cyanide
CN-1
Hydroxide
OH-1
Carbonate
CO3-2
Phosphate
PO4-3
Chromate
CrO4-2

11. Name Formula Name Formula
Sulfite
SO3-2
Hydrogen Carbonate
HCO3-1
Sulfate
SO4-2
Hydrogen Phosphate
HPO4-2
Hydrogen Sulfite
HSO3-1
Hydrogen Sulfate
HSO4-1
Permanganate
MnO4-1
Oxalate
C2O4-2
Hydronium
H3O+
Silicate
SiO3-2
Peroxide
O2-2
Phosphite
PO3-3
Bromate
BrO3-1
Arsenate
AsO4-2

12. Naming Compounds with Polyatomic Ions
Formula Name
(NH4)2SO ammonium sulfate
ZnCO3 zinc carbonate
NH4Br ammonium bromide
Li2CO3 lithium carbonate
* Polyatomic & monatomic cation names remain the same, monatomic anions change their ending to –ide.

13. Writing Ionic Compound Formulas
Example: Barium nitrate
Ba2+
( )
NO3- 2
1. Write the formulas for the cation and anion, including CHARGES!
Not balanced!
2. Check to see if charges are balanced.
3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion.

14. Writing Ionic Compound Formulas
Example: Ammonium sulfate
( )
NH4+
SO42- 2
1. Write the formulas for the cation and anion, including CHARGES!
Not balanced!
2. Check to see if charges are balanced.
3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion.

15. Writing Ionic Compound Formulas
Example: Aluminum sulfide
Al3+
S2- 2 3
1. Write the formulas for the cation and anion, including CHARGES!
Not balanced!
2. Check to see if charges are balanced.
3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion.

16. Writing Ionic Compound Formulas
Example: Magnesium carbonate
Mg2+
CO32-
1. Write the formulas for the cation and anion, including CHARGES!
2. Check to see if charges are balanced.
They are balanced!
3. Simplify to a formula unit.

17. Writing Ionic Compound Formulas
Example: Zinc hydroxide
Zn2+
( )
OH- 2
1. Write the formulas for the cation and anion, including CHARGES!
Not balanced!
2. Check to see if charges are balanced.
3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion.

18. Writing Ionic Compound Formulas
Example: Aluminum phosphate
Al3+
PO43-
1. Write the formulas for the cation and anion, including CHARGES!
They ARE balanced!
2. Check to see if charges are balanced.

19. Chemical Formula Chemical Name
More Examples…
Chemical Formula Chemical Name
Cr2O3
Cr2O
CuSO4
Ni(OH)2
Cr2(C2O4)3
Cu2S
CuS
chromium (III) oxide
chromium (I) oxide
copper (II) sulfate
nickel (II) hydroxide
chromium (III) oxalate
copper (I) sulfide
copper (II) sulfide

20. Naming Binary Covalent Compounds
Compounds between two nonmetals
First element in the formula is named first.
Second element is named as if it were an anion.
Use prefixes
Only use mono on second element
P2O5 =
diphosphorus pentoxide
CO2 =
carbon dioxide
CO =
carbon monoxide
N2O =
dinitrogen monoxide

21. Covalent compounds Prefixes
# of water molecules
prefix 1
mono- 6
hexa- 2
di- 7
hepta- 3
tri- 8
octa- 4
tetra- 9
nona- 5
penta- 10
deca-

22. Chapter 7 Chemical Formulas & Chemical Compounds
7.2 Oxidation Numbers

23. Oxidation Numbers
Oxidation Number – numbers assigned to atoms composing a compound or ion that indicate the general distribution of electrons among bonded atoms