1. Naming Compounds
Names and Formulas

3. Writing Chemical Formulas
1 – what elements
2 - ratios in compound
Metals(positive ions) written first
Polyatomic Ions:
group of atoms that act as an element
has its own ionic charge
Always look on the Data Table for
name and
ion charge

4. Ion Charge and the Formulas of Ionic Compounds
Law of Definite Proportions:
a specific compound elements are always in definite proportions; integers no decimals or fractions
Ex: H2O – always 2 hydrogen atoms for one oxygen atom
Ionic compounds:
metal + non-metal
Electron(s) transferred
bonded by electrical force (opp. charges attract)
electrically neutral

5. Ion Charge and the Formulas of Ionic Compounds
metal + non-metal
Positive ion + negative
Cation + Anion

6. Formulas of Ionic Compounds
Use Cross-over Rule:

7. Ion Charge and the Formulas of Ionic Compounds
Formulas for Ionic Compounds with Polyatomic Ions:
Use crossover rule but
Polyatomic Ions --- MUST BE KEPT TOGETHER
Use brackets around polyatomic groups if there is more than 1

8. Ion Charge and the Formulas of Ionic Compounds
multivalent:
element with more than 1 possible ion charge;
occurs only after atomic # 20 – Ca
Are in Transition metals on PT
Use crossover rule
When naming the CHARGE is written in roman numerals ex. Iron(III)oxide

9. Naming Ionic Compounds
Rules for Naming Ionic Compounds:
Metal(pos) ion written 1st
name spelled same in lower case
non-metal ion written 2nd
given suffix “–ide”

10. Naming Ionic Compounds
Naming Polyatomic Ions:
pos. polyatomic ions written 1st
neg. polyatomic ions written 2nd; name of ion not changed
Use the data table
Do Exercise #4

11. Naming Ionic compounds using the formula
Example 1: Ag2SO4
Silver is monovalent, so, no Roman Num. necessary
Look up SO4 on table – sulphate
Therefore, name is Silver sulphate
Example 2: Cu2O
look at the total amt of charge on each half of formula:
The neg side O for oxygen is monovalent – has charge of 2-
Therefore the pos side must have a charge of 2+
As there are 2 Cu, the charge on each Cu must be 1+
(1+ plus 1+ equals 2+)
Therefore the name of the compound must be
Copper(I) oxide
(remember multivalents must use Roman Numerals in the name)

12. Naming Ionic compounds using the formula
Example 3: FeS
Iron(Fe) is multivalent, so, Roman Num. necessary
Look up S on Periodic table – has a 2- charge
So, Fe must have a 2+ charge to balance
Therefore the name is Iron(II) sulphide
Example 4: Fe2(HPO4)3
look at the total amt of charge on each half of formula:
The neg side: eacg HPO4 has charge of 2-
There are 3 HPO4 the neg side must have a charge of 6- (3 x 2- = 6-)
As there are 2 Fe, the charge on each Fe must be 3+
(3+ plus 3+ equals 6+)
Therefore the name of the compound must be
Iron(III) monohydrogen phosphate
(remember multivalents must use Roman Numerals in the name)

13. Naming Ionic compounds using the formula
Try It:
1 – Ag3PO4
2 – Al2(SO4)3
3 – Fe2S3
4 – CuCl
5 – (NH4)2CO3
6 – VCl3
7 – Hg2CO3
8 – CuSO4
9 – (NH4)2S
Answers:
1 – Silver phosphate
2 – Aluminum sulphate
3 – Iron(III) sulphide
4 – Copper(I) chloride
5 – Ammonium carbonate
6 – Vanadium(III) chloride
7 – Mercury(I) carbonate
8 – copper(II) sulphate
9 – Ammonium sulphide

14. Naming Ionic compounds using the formula
Do Exercise #5
Do Handout: Writing formulas Quiz
(exercise in Names -> Formulas)
Do Handout: Formula Writing
Do Handout: Inorganic Nomenclature Test (may do as Test or Quiz)

15. Naming Ionic compounds using the formula Hydrates
When a crystal of an ionic compound is grown by evaporation from aqueous solution, frequently it is found that the crystal structure will include water molecules
Molecules which include water molecules are called HYDRATES
Use prefixes to tell how many water molecules are attached;

16. Naming Ionic compounds using the formula Prefixes for Hydrates
mono di
tri
tetra
penta
hexa
hepta
octa
nona
deca 1 2 3 4 5 6 7 8 9 10

17. Naming Ionic compounds using the formula Prefixes for Hydrates
Examples:
CuSO4*5H2O
Zn(CH3COO)2*2H2O
Ca(NO3)2*4H2O
Copper(II)sulphate pentahydrate
Zinc acetate dihydrate
Calcium nitrate tetrahydrate
Do exercise #6 & #7

18. Naming Covalent Compounds
Unlike Ionic compounds there are several various combinations of elements possible.
Ionic example: sodium and chlorine
always forms NaCl
It is the ONLY possible combination
This combination is called a formula unit; NOT a molecule
Covalent example: carbon and oxygen

19. Naming Covalent Compounds
Unlike Ionic compounds, Covalent compounds has numerous possibilities in how the elements can combine:
Example: carbon and oxygen
Can form CO or CO2 or CO3
Each has unique properties:
CO will kill you while CO2 will not
You cannot all these variations carbon oxide
A different naming system is necessary

20. Naming Covalent Compounds
Prefix naming system – use prefixes to name the various covalent molecules
Note: these are molecules not formula units as with Ionic compounds
Examples of naming covalent molecules:
carbon and oxygen can form CO or CO2 or CO3
CO is named carbon monoxide
CO2 is named carbon dioxide
CO3 has a special name carbonate – a polyatomic structure

21. Naming Covalent Compounds
Prefixes indicates the number of the types of atoms in a molecule
mono di
tri
tetra
penta
hexa
hepta
octa
nona
deca 1 2 3 4 5 6 7 8 9 10

22. Naming Covalent Compounds
Rules for prefixes:
1 - don’t use mono for the first element if there is only one;
2 - always use mono for second element if there is only one atom in the molecule
3 - mono drops the 2nd “o” as in carbon monoxide
4 - second element ends with ‘ide’
5 – add the appropriate prefix according to number of atoms present in molecule

23. Naming Covalent Compounds
The name of the molecule always reflects the structure of the molecule
Example: P4O tetraphosphorus decaoxide
You can tell what the formula is by looking at the name; or
You can tell what the name is by looking at the formula
This makes covalent compounds easy to name and easy to write the formula

24. Naming Covalent Compounds
REMEMBER: always determine to see if the compound is
IONIC or
COVALENT
Then follow the appropriate rules
Do Exercise #8 & 9
Handout:
Nomenclature
Flow Chart

25. Naming Acids 2 types of acids: 1 -- has NO oxygen examples:
name begins with ‘hydro’
ends with ‘ic’
examples:
HF – hydrogen fluoride
HCl – hydrogen chloride
hydrofluoric acid
hydrochloric acid

26. Naming Acids 2 -- has oxygen examples:
There are 2 types of acids WITH oxygen:
One type the chemical name ends with “ite” as in hydrogen sulphite
The other the chemical name ends with ”ate” as in hydrogen carbonate
examples:
Formula Chemical Name:
H2SO3 – hydrogen sulphite
H2CO3 – hydrogen carbonate
sulphurous acid
carbonic acid
for both there is NO ‘hydro’ in the name
“ite” becomes ous
”ate” becomes ic