Chemical Nomenclature
Chemical Nomenclature
Ions
Ionic Charges of
Representative Elements
AP Chemistry (1 of 20)
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Chemical Nomenclature
Chemical Nomenclature
Formulas and Names of Common
Metal Ions with More than One
Common Ionic Charge
Some Common
Polyatomic Ions
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Chemical Nomenclature
Chemical Nomenclature
Naming Monatomic Ions
Naming Polyatomic Ions
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AP Chemistry (6 of 20)
Chemical Nomenclature
Chemical Nomenclature
Writing Formulas for Binary
Ionic Compounds
Naming Binary Ionic
Compounds
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AP Chemistry (8 of 20)
1
Ionic Charges of Representative Elements
Ions
Ions are charged particles formed when an atom gains or loses
electrons. Monatomic ions are ions consisting of only one
element. Polyatomic ions are tightly bound groups of atoms
that behave as a unit and carry a charge.
Ionic Charges of Representative Elements
1A
2A
3A
5A
6A
7A
Be2+
N3O2FLi+
+
2+
3+
32Na
Mg
Al
P
S
Cl+
2+
32Ca
As
Se
BrK
+
2+
Rb
Sr
I+
2+
Ba
Cs
Cations are positively charged ions formed when atoms lose
electrons. Metals tend to form cations.
Anions are negatively charged ions formed when atoms gain
electrons. Nonmetals tend to form anions.
Formulas and Names of Common Metal Ions with
More than One Common Ionic Charge
Some Common Polyatomic Ions
1- Charge
ClOhypochlorite
chlorite
ClO2ClO3chlorate
perchlorate
ClO4NO2nitrite
nitrate
NO3CNcyanide
OHhydroxide
C2H3O2- acetate
2- charge
sulfite
SO32SO42sulfate
CO32carbonate
CrO42chromate
Cr2O72- dichromate
SiO32silicate
oxalate
C2O42-
PO33PO43-
3- charge
phosphite
phosphate
NH4+
1+ Charge
ammonium
Formula
Cu+
Cu2+
Fe2+
Fe3+
Hg22+
Hg2+
Pb2+
Pb4+
Name
Copper(I) ion
Copper(II) ion
Iron(II) ion
Iron(III) ion
Mercury(I) ion
Mercury(II) ion
Lead(II) ion
Lead(IV) ion
Formula
Sn2+
Sn4+
Cr2+
Cr3+
Mn2+
Mn3+
Co2+
Co3+
Name
Tin(II) ion
Tin(IV) ion
Chromium(II) ion
Chromium(III) ion
Manganese(II) ion
Manganese(III) ion
Cobalt(II) ion
Cobalt(III) ion
Note: Zn2+, Cd2+, and Ag+ do not require Roman numerals when naming
them because these metals only have one common ionic charge.
Naming Polyatomic Ions
Naming Monatomic Ions
Monatomic anions are named by adding the ending –ide to the root .
Example: F- is the fluoride ion
The names of most polyatomic anions end in –ite or –ate.
However, there are three important exceptions: the positively
charged ammonium cation (NH4+) and two polyatomic anions
that end in –ide, the cyanide ion (CN-) and the hydroxide ion
(OH-).
Monatomic cations are identified simply by the element’s name.
Example: Ca2+ is the calcium ion
Some metals have more than one common ionic charge. A Roman
numeral indicating the charge of the ion must be used when naming
these ions.
Example: Fe2+ is the iron(II) ion and Fe3+ is the iron(III) ion
The –ite form of a polyatomic ion contains one less oxygen
than the –ate form.
Example: SO32- is sulfite, SO42- is sulfate
Naming Binary Ionic Compounds
Writing Formulas for Binary Ionic Compounds
Empirical formulas (lowest whole number ratio of the atoms in a
compound) are used when writing the formulas for ionic
compounds.
Steps in writing a formula for a binary ionic compound:
1. Identify the ions involved.
2. Balance the charges. The overall charge for an ionic
compound is zero.
Examples:
Barium sulfide
Ba2+, S2BaS
Lead(II) phosphide
Pb2+, P3Pb3P2
Binary ionic compounds are named by first naming the cation
and then naming the anion. The name of a monatomic anion
ends in -ide. Remember to use a Roman numeral with the
cations that have more than one common ionic charge.
Examples:
LiCl
Lithium chloride
Ba3N2 Barium nitride
Fe2O3 Iron(III) oxide
2
Chemical Nomenclature
Chemical Nomenclature
Writing Formulas for
Ternary Ionic Compounds
Naming Ternary Ionic
Compounds
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Chemical Nomenclature
Chemical Nomenclature
Binary Molecular Compounds
Prefixes Used in Naming
Binary Molecular Compounds
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Chemical Nomenclature
Chemical Nomenclature
Naming Binary Molecular
Compounds
Writing Formulas for Binary
Molecular Compounds
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Chemical Nomenclature
Chemical Nomenclature
Acids
Naming Binary Acids
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3
Naming Ternary Ionic Compounds
Writing Formulas for Ternary Ionic Compounds
Ternary ionic compounds are named by first naming the cation
and then naming the anion. Remember to use a Roman
numeral with the cations that have more than one common
ionic charge.
Examples:
Na2SO3
Cr3(PO4)2
NH4Cl
You write the formula for a ternary ionic compound the same
way as you do for a binary ionic compound. However,
parenthesis must be used to indicate more than one of a
polyatomic ion.
Examples:
Copper(II) sulfate
Ammonium phosphate
Silver carbonate
sodium sulfite
chromium(II) phosphate
ammonium chloride
Prefixes are used to show how many atoms of each element are
present in each molecule of a molecular compound.
1
2
3
4
5
hexaheptaoctanonadeca-
CuSO4
(NH4)3PO4
Ag2CO3
Binary Molecular Compounds
Prefixes Used in Naming Binary Molecular Compounds
monoditritetrapenta-
Cu2+, SO42NH4+, PO43Ag+, CO32-
Binary molecular compounds are composed of two nonmetallic
elements. The ionic charges are not used in writing formulas
for molecular compounds. When two nonmetallic elements
combine, they often do so in more than one way.
6
7
8
9
10
Ex. CO2, CO
Naming Binary Molecular Compounds
Writing Formulas for Binary Molecular Compounds
The names of molecular compounds have this form: (prefix +
element name) (prefix + element root + ide)
Ex. Cl2O3 is dichlorine trioxide
Do not balance the ionic charges when writing formulas for
binary molecular compounds. Write down the number of
atoms of each element indicated by the name.
Ex.
dinitrogen tetrahydride
N 2H 4
sulfur dioxide
SO2
Note: The prefix mono is usually omitted if there is just a single
atom of the first element.
Example: CO2 is carbon dioxide.
A few inorganic molecular compounds have common names
that all scientists use in place of formal names. CH4 is
methane, H2O is water and NH3 is ammonia.
Note: If the vowel combinations o-o or a-o appear next to each
other in the name, the first of the pair is omitted to simplify the
name.
Example: N2O is dinitrogen monoxide
Naming Binary Acids
Acids
Acids are compounds that produce hydrogen ions (H+) in
solution. Two common types of acids exist – binary acids and
oxyacids.
Binary acids have the general formula of H + Nonmetal.
They are named by writing hydro + root + ic acid
Ex.
HCl
H2S
Ex. HI
HNO2
Hydrochloric acid
Hydrosulfuric acid
4
binary acid
oxyacid
(hydroiodic acid)
(nitrous acid)
Chemical Nomenclature
Chemical Nomenclature
Writing Formulas
for Binary Acids
Oxyacids
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Chemical Nomenclature
Chemical Nomenclature
Naming Oxyacids
Writing Formulas
for Oxyacids
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Chemical Nomenclature
Chemical Nomenclature
AP Chemistry
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Chemical Nomenclature
Chemical Nomenclature
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5
Oxyacids
Writing Formulas for Binary Acids
Oxyacids are acids that contain hydrogen and an oxyanion. An
oxyanion is a polyatomic ion that contains oxygen and another
element (usually a nonmetal). Oxyacids have the general
formula H + polyatomic ion.
The charges must be balanced when writing the formulas for
binary acids.
Hydrofluoric acid
Hydroselenic acid
Ex. HIO3 iodic acid
Writing Formulas for Oxyacids
H+, FH+, S2-
HF
H2Se
Naming Oxyacids
There are two methods used to help name acids.
First method:
Ending of
Acid
Example
Polyatomic Ion
Ending
-ate
-ic
HBrO3 bromic acid
-ite
-ous
HClO2 chlorous acid
Second method:
reference form
HClO3 chlorIC acid
HClO2 chlorOUS acid
1 less oxygen
HClO HYPOchlorOUS acid
2 less oxygen
1 more oxygen
HClO4 PERchlorIC acid
When writing formulas for oxyacids, you must always balance the
charges.
Ex.
comes from nitrite
(1 less O than the refererence)
Nitrous acid
H+, NO2- HNO2
comes from carbonate (reference)
Carbonic acid
H+, CO32- H2CO3
Periodic acid
comes from periodate (1 more O than the reference)
HIO4
H+, IO4Hyponitrous acid comes from hyponitrite (2 less O than the reference)
HNO
H+, NO-
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