1. Chapter 8. Chemical Nomenclature
Chemical nomenclature is the system of names used to distinguish chemical compounds from each other, and the rules needed to devise these names.

2. Chemical Nomenclature
Why Bother?
How do you speak Al2(SO4)3 ?
What system do we use?
IUPAC International Union of Pure and Applied Chemistry

3. Chemical Nomenclature
Three major categories of compounds:
Ionic
First element in formula is a metal.
Molecular
First element in formula is a nonmetal.
Acid
First element in formula is Hydrogen.

4. Naming Ionic Compounds
Types of ionic compounds:
Binary, contains two elements:
NaCl, MgBr2, Fe2O3
Ternary, contains three elements; two are in a polyatomic anion:
NaNO3, NH4Cl, Cr2(SO4)3

5. Naming Binary Ionic Compounds
What is the charge on the metal ion?
Fixed: Group 1A, +1; Group 2A, +2
Al3+, Ga3+, Zn2+, Cd2+, Ag1+
Examples: NaCl, Al2O3, CdS
Name cation as element, e.g. sodium
Name anion with stem of element name, followed by suffix ide, e.g. chloride

6. Naming Binary Ionic Compounds
What is the charge on the metal ion?
Variable: All other metals
Examples: CuO, FeBr2, Fe2O3
Name cation as element, followed by charge in Roman numerals, enclosed by parentheses, e.g. copper(II)
Name anion with stem of element name, followed by suffix ide, e.g. oxide

7. Naming Binary Ionic Compounds
What is the charge on the metal ion?
The compound must be electrically neutral.
Use the charge on the anion to figure out the charge on the metal.
Examples: FeO, Fe2O3
CuCl, CuCl2
SnF2, SnF4
Hg2Cl2, HgCl2

8. Naming Binary Ionic Compounds
An older naming system gives the suffix ic to the ion with the higher charge, and the suf-fix ous to the ion with the lower charge, following the (usually Latin) element stem.
FeO ferrous oxide; Fe2O3 ferric oxide
CuCl cuprous chloride CuCl2 cupric chloride
SnF2 stannous fluoride SnF4 stannic fluoride
Hg2Cl2 mercurous chloride HgCl2 mercuric chloride

9. Naming Ternary Ionic Compounds
Name metal as you would for a binary, with charge if necessary.
Name anion as itself. Know these:
CO32- carbonate ClO1- hypochlorite
NO31- nitrate ClO31- chlorate
PO43- phosphate C2H3O21- acetate
SO42- sulfate CH3COO1- acetate
OH1- hydroxide CN1- cyanide

10. Naming Ternary Ionic Compounds
There is one polyatomic cation
NH41+, ammonium
Name it, then name anion properly

11. Formulas from Names Write symbol for metal ion first, then anion.
Use the charges on the ions to determine how many of each ion are present in the formula. Charges must sum to zero.
If a polyatomic ion appears more than once in a formula, enclose it in parentheses, followed by a subscript showing the number of times the ion occurs in the compound.

12. Practice Give Name Give Formula CaCl2 Mercurous iodide
Mg(NO3)2 Mercury(II) iodide
Al2(SO4)3 Silver nitrate
FeCl3 Ammonium bromide
AgBr Tin(II) hydroxide
MnO2 Sodium cyanide
NH4NO3 Calcium phosphate

13. Naming Molecular Compounds
These are all binary. Since the atoms do not have charges, use Greek numerical prefix-es to indicate the number of each atom in the molecule.
Know these:
1 mono 4 tetra
2 di penta
3 tri hexa

14. Naming Molecular Compounds
How to name them:
1. Prefix for first element in formula, omit if it's "mono"
2. Name first element
2. Prefix for second element in formula,
3. Give stem of second element followed by suffix ide.
CO Carbon monoxide
CO2 Carbon dioxide
N2O Dinitrogen monoxide

15. Naming Molecular Compounds
Details and exceptions:
If last letter of prefix for number and first letter of element are both vowels, drop the last letter of the prefix:
CO carbon monoxide
N2O5 dinitrogen pentoxide
Some compounds are known only by common names.
H2O water NH3 ammonia

16. Formulas from Names
Write symbol for least electronegative element first, then most electronegative.
Use prefixes to determine subscripts in formula.
Metalloids are not metals, and their com-pounds are named as molecular com-pounds.

17. Practice Give Name Give Formula NO2 Carbon tetrachloride
SO3 Phosphorus trichloride
SiO2 Selenium dibromide
TiO2 Dinitrogen tetroxide
NO Sulfur dioxide
P2O5 Xenon tetrafluoride
Fe2O3 Diantimony Trioxide

18. Naming Acids Types of acids: Binary, contains two elements:
HCl, HBr, H2S
Ternary, contains three elements; two are in a polyatomic ion:
HNO3, H2SO4, H3PO4

19. Naming Binary Acids Binary acids are gases as pure compounds.
Symbol: HCl or HCl (g)
Name: hydrogen + stem of nonmetal followed by suffix -ide.
hydrogen chloride

20. Naming Binary Acids
The compounds become acidic in water solution (aqueous solution); they ionize.
HCl + H2O  H3O Cl1-
H3O1+ is what makes acids acidic.
Symbol: HCl (aq)
Name: prefix hydro- + stem of nonmetal followed by suffix -ic acid.
hydrochloric acid

21. Naming Ternary Acids
No distinction is made between pure ternary acids and those in aqueous (water) solution.
Symbol: H2SO4
Name: stem of central atom followed by suffix -ic acid.
sulfuric acid

22. Naming Ternary Acids
Know names of these ternary acids. They are related to "must know" polyatomic anions:
H2CO3 HClO
HNO3 HClO3
H3PO HC2H3O2
H2SO4 CH3COOH
HOH HCN (aq)

23. Naming Acids and Anions
Useful Generalization:
If the name of an anion ends in -ide, its aqueous acid is named as hydrostemic acid.
If the name of an anion ends in -ate, its acid is named as stemic acid.

24. Practice Give Name Give Formula HBr (aq) Sulfuric acid
HNO3 Carbonic acid
H2O Hydrogen iodide
H2S Hypochlorous acid
HF Hydrocyanic acid
H3PO4 Acetic acid
HI (aq) Chloric acid

25. Naming Mixed Salts
Mixed salts are compounds in which Na1+ or K1+ combine with H1+ and an anion with -2 or -3 charge.
Symbol: KHSO4
Name: metal cation, hydrogen, anion
Potassium hydrogen sulfate

26. Naming Mixed Salts
If the anion has -3 charge (PO43-), three cations are required to form a neutral compound.
Symbol: NaH2PO4
Name: metal cation, prefix di-hydrogen, anion Sodium dihydrogen phosphate
Symbol: K2HPO4
Name: prefix di-metal cation, hydrogen, anion Dipotassium hydrogen phosphate

27. More Practice Give Name Give Formula AgNO3 Magnesium sulfate
CaS Ferric chloride
NH3 Nitric acid
NaHS Lead(IV) sulfate
ZrO2 Sodium hydrogen carbonate
H2SO4 Mercuric bromide
Al2O3 Phosphorus trifluoride