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
Type III - Binary Compounds of 2
Nonmetals
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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
• Prefixes: 1-mono, 2-di, 3-tri, 4-tetra,5-penta,
6-hexa, 7-hepta, 8-octa, 9-nona, 10-deca, 11undeca, 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
Writing Formulas
Naming Compounds
• SiF2 - silicon difluoride• Nitrogen trichloride – NCl3
• C3Cl9 - tricarbon
nonachloride
• Triphosphorus pentoxide - P3O5
• Hexasulfur monofluoride - S6F
• S4I7 – tetrasilicon
heptaiodide
• Diselenium pentabromide –
Se2Br5
• P5O10 – pentaphosphorus
octoxide
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 from the
charge on anion
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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 #3 Ions & Symbols List)
•
Nonmetal anion named by changing the ending
on the nonmetal name to -ide
Naming Binary Type II Compounds
• Cu+1 and N-3
• Iron (III) phosphide
• Hg+2 and O-2
• Manganese (II) fluoride
• Cr+3 and P-3
• Gold (I) telluride
• Sn+4 and Cl-1
• Lead (IV) bromide
• Ni+4 and S-2
• 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 Ionic Compounds Examples
• Au2S
• NiS2
• MnO
• Cr3P2
• Fe3N2
• PbF4
• CuCl2
• HgI
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 sulfate
Ca+2 and SO4-2
• Sodium chlorate
Na+1 and ClO3-1
• Magnesium hydroxide
Mg+2 and OH-1
• Potassium phosphate
K+1 and PO4-3
• Iron (III) carbonate
Fe+3 and CO3-2
• Tin (IV) chromate
Sn+4 and CrO4-2
• Nickel (II) dihydrogen
phosphate
Ni+2 and H2PO4-1
• Chromium (III) sulfate
Cr+3 and SO4-2
• Copper (II) acetate
Cu+2 and C2H3O2-1
• Iron (II) permanganate
Fe+2 and MnO4-1
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
• Ni3(PO3)4
• KClO3
• Fe(CN)2
• BaSO3
• Mn(HCO3)3
• AlPO4
• Au2CO3
• CuOH
• Cr2HPO4
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
Writing Formulas for Acids
• Sulfuric acid
• HI
• Hydroarsenic acid
• HCN
• Perchloric acid
• H2C4H4O6
• Hypoiodous acid
Hydrates
• Hydrates are when you have a certain
number of water molecules attached to a
compound (usually an ionic compound)
• The number of water molecules is shown
after the formula for a compound and
separated from the remainder of the
compound by a dot.
Hydrates
• Use the same prefixes as you did when
naming binary molecular compounds to
tell how many water molecules are present
in a hydrate (1 = mono, 2 = di, …)
• An anhydrous compound is one that
contains no water molecules.
Hydrate Examples
. 5H O
• Mg(NO ) . 3 H O
• CuSO4
2
3 2
2
• Barium chloride dihydrate
• Ammonium acetate octahydrate
Basic Organic Compounds
• You will need to know the names of the
first 10 alkanes (hydrocarbons containing
only single bonds).
• The generic formula of these alkanes is:
•CnH2n+2
Basic Organic Compounds
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Methane – CH4
Ethane – C2H6
Propane – C3H8
Butane – C4H10
Pentane – C5H12
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Hexane - C6H14
Heptane - C7H16
Octane - C8H18
Nonane - C9H20
Decane - C10H22