Nomenclature
Chapter 5
Classifying Binary Compounds
• Compounds containing a metal and a nonmetal are binary ionic– Type I and II
• Compounds containing two nonmetals– Type III
• Compounds containing H and a nonmetal = Acids
Metal Cations
• Type I – Metals that can only have one possible charge– Determine charge by position on the Periodic
Table
• Type II– Metals that can have more than one possible
charge– Determine metal cation’s charge using the
charge on anion
Type II Binary Ionic Compounds
• Contain Metal Cation + Nonmetal Anion• Metal listed first in formula & name• Name metal cation first, name nonmetal anion
second• Metal cation name is the metal name followed by
a Roman Numeral in parentheses to indicate its charge– Determine charge from anion charge– Common Type II cations in Table 5.2 (page 128 or on
Week #2 Ions & Symbols List)• Nonmetal anion named by changing the ending
on the nonmetal name to -ide
Writing Formulas for Binary Type II Compounds
• Cu+1 and N-3
• Hg+2 and O-2
• Cr+3 and P-3
• Sn+4 and Cl-1
• Ni+4 and S-2
• Iron (III) phosphide
• Manganous fluoride
• Gold (I) telluride
• Plumbic bromide
• Cobalt (III) arsenide
Ionic Compounds
• Sometimes you can use the reverse of the criss-cross method to determine the charges for the transition metals.
• When naming compounds, you do not need to tell how many atoms of each ion are present.
Naming Binary Type II Compounds
• Au2S
• MnO
• Fe3N2
• CuCl2
• NiS2
• Cr3P2
• PbF4
• HgI
Type III - Binary Compounds of 2 Nonmetals
• These binary compounds always start with a nonmetal or a metalloid. That’s the easiest way to identify them. They will contain no metals!
• Name first element in formula first, use the full name of the element
• Name the second element in the formula as if it were an anion– However, remember these compounds do not contain
ions, so DO NOT USE THE CRISS-CROSS METHOD!!!
Type III Binary Molecular Compounds
• Use a prefix in front of each name to indicate the number of atoms
• Never use the prefix mono- on the first element but always put a prefix on the second element.
• Prefixes: 1-mono, 2-di, 3-tri, 4-tetra,5-penta, 6-hexa, 7-hepta, 8-octa, 9-nona, 10-deca, 11-undeca, 12-dodeca.
• To write the formula for binary molecular compounds, write the number next to the compound if there is a prefix, if not just write the symbol itself.
Binary Molecular Compounds Examples
Naming Compounds
• SiF2
• C3Cl9
• S4I7
• P5O10
Writing Formulas• Nitrogen trichloride
• Triphosphorus pentoxide
• Hexasulfur monofluoride
• Diselenium pentabromide
Figure 5.1: A flow chart for naming
binary compounds.
Ionic Compounds
• Ternary ionic compounds – contain atoms of three or more different elements, usually a polyatomic ion.
• Writing the formulas for ternary compounds is done in the same way as binary compounds. The polyatomic ions stays together though.
Ionic Compounds
• When you need more than one polyatomic ion in your formula, put parentheses around the ion, and how many of them you need outside the parentheses as a subscript.
• NEVER MOVE SUBSCRIPTS OF THE IONS, ONLY THE CHARGES!!!
Writing Formulas for Ternary Ionic Compound Examples
• Calcium hydrogen sulfate
• Sodium chlorate
• Magnesium hydroxide
• Potassium phosphate
• Aluminum acetate
• Tin (IV) chromate
• Nickel (II) dihydrogen phosphate
• Chromium (III) sulfate
• Copper (II) acetate
• Iron (II) permanganate
Ionic Compounds
• When naming ternary compounds, name the cation (first symbol in the formula unless it is ammonium, NH4
+1) first, and then the rest of the formula, which will only have one name, unless it contains hydrogen.
Naming Ternary Ionic Compounds
• Ca(NO3)2
• KClO3
• BaSO3
• AlPO4
• (NH4)3BO3
• Ni3(PO3)4
• Fe(CN)2
• Mn(HCO3)3
• Au2CO3
• Cr2HPO4
Naming Compounds Containing a metal with more than one possible charge and a
Polyatomic ion• Ni3(PO3)4
• Fe(CN)2
• Mn(HCO3)3
• Au2CO3
• Cr2HPO4
• CuOH
• Sn(SO3)2
• Co3(BO3)2
• Hg(C2H3O2)2
Acids
Naming & Writing Formulas for Acids
• All acids begin with a hydrogen, and are neutral compounds.
• In all acids, the cation is the hydrogen ion, H+1.
• Anions change their endings when they become acids.
Acids• -ide ions become hydro root ic acid• Ex: chloride becomes hydrochloric acid
• -ate ions become root ic acid• Ex: nitrate becomes nitric acid
• -ite ions become root ous acid• Ex: chlorite becomes chlorous acid
Acids Naming & Formula Writing Examples
Naming Acids
• H3PO3
• HI
• HCN
• H2C4H4O6
Writing Formulas for Acids• Sulfuric acid
• Hydroarsenic acid
• Perchloric acid
• Hypochlorous acid
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