1. Mr. Matthew Totaro Legacy High School Regular Chemistry
Chemical Formulas and Chemical Nomenclature
Mr. Matthew Totaro
Legacy High School
Regular Chemistry

2. Molecular View of Elements and Compounds

3. Classifying Materials
Atomic elements = Elements whose particles are single atoms
Molecular elements = Elements whose particles are multi-atom molecules
Molecular compounds = Compounds whose particles are molecules made of only nonmetals
Ionic compounds = Compounds whose particles are cations and anions

4. Classify Each of the Following as Either an Atomic Element, Molecular Element, Molecular Compound, or Ionic Compound
Aluminum, Al
Aluminum chloride, AlCl3
Chlorine, Cl2
Acetone, C3H6O
Carbon monoxide, CO
Cobalt, Co

5. Classify Each of the Following as Either an Atomic Element, Molecular Element, Molecular Compound, or Ionic Compound (Continued)
Aluminum, Al = Atomic element
Aluminum chloride, AlCl3 = Ionic compound
Chlorine, Cl2 = Molecular element
Acetone, C3H6O = Molecular compound
Carbon monoxide, CO = Molecular compound
Cobalt, Co = Atomic element

6. Law of Constant Composition

7. Law of Constant Composition
All pure substances have constant composition
All samples of a pure substance contain the same elements in the same percentages (ratios)
Mixtures have variable composition

8. Chemical Nomenclature
To name a substance, first figure out what elements you have
Metal or Nonmetal?

9. Metal and Nonmetal Nomenclature
Metals: Cations (Groups 1A, 2A, 3A)
Metal cation name DOES NOT change
Nonmetals: Anions (Groups 5A, 6A, 7A)
Nonmetal anion: change ending to –IDE
Example:
Ca+2: Calcium NaCl: Sodium chloride
Cl-: Chloride MgO: Magnesium oxide
O-2: Oxide

10. Practice — Name the Following Compounds
KCl
MgBr2
Al2S3

11. Practice—Name the Following Compounds (Continued)
KCl potassium chloride.
MgBr2 magnesium bromide.
Al2S3 aluminum sulfide.

12. Transition Metal and Nonmetal Nomenclature
Transition Metal: Cation (Group B elements)
Stock System: Use Roman numerals to identify the charge of the metal
I = 1 III = 3 V = 5 VII = 7
II = 2 IV = 4 VI = 6
Example: Mn+2: Manganese (II), Fe+3: Iron (III)
Nonmetals: Anions (Groups 5A, 6A, 7A)
Nonmetal anion: change ending to –IDE

13. Transition Metal and Nonmetal Nomenclature (Continued)
Examples:
Fe+2O-2: Iron (II) oxide
TiO2: Titanium (IV) oxide
If charge is not shown, look at Group number
Titanium is in Group 4B

14. Practice ─ Name the Following Compounds
TiCl4
PbBr2
Fe2S3

15. Practice ─ Name the Following Compounds, Continued.
TiCl4 Titanium(IV) chloride
PbBr2 Lead(II) bromide
Fe2S3 Iron(III) sulfide
Cl = 4(−1) = −4
Ti = +4 = 1(4+)
Br = 2(−1) = −2
Pb = +2 = 1(2+)
S = 3(−2) = −6
Pb = +6 = 2(3+)

16. Nonmetal and Nonmetal Nomenclature
1st Nonmetal: name DOES NOT change
2nd Nonmetal: change ending to –IDE
To identify quantity, use prefixes
Example:
NO2: Nitrogen dioxide
PCl5: Phosphorus pentachloride
I2F7: Diiodine heptaflouride
CO: Carbon monoxide

17. Subscript—Prefixes 1 = mono- 2 = di- 3 = tri- 4 = tetra- 5 = penta-
Not used on first nonmetal.
2 = di-
3 = tri-
4 = tetra-
5 = penta-
6 = hexa-
7 = hepta-
8 = octa-
Drop last “a” if name begins with vowel.

18. Example—Naming Binary Molecules
BF4
N2O4
Cl5O5

19. Example—Naming Binary Molecules
BF4 Boron tetraflouride
N2O4 Dinitrogen tetroxide
Cl5O5 Pentachlorine pentoxide

20. Common Names—Exceptions
H2O = Water, steam, ice.
NH3 = Ammonia.
CH4 = Methane.
NaCl = Table salt.
C12H22O11 = Table sugar.