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

Molecular View of Elements and Compounds

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

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

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

Law of Constant Composition

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

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

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

Practice — Name the Following Compounds KCl MgBr2 Al2S3

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

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

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

Practice ─ Name the Following Compounds TiCl4 PbBr2 Fe2S3

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+)

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

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.

Example—Naming Binary Molecules BF4 N2O4 Cl5O5

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

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