CHAPTER 7
LANGUAGE OF CHEMISTRY
CLASSIFICATION OF COMPOUNDS
Inorganic compounds does not contain the element carbon, but there
are exception to this rule, CO2 (carbon dioxide), CO32-(carbonate), and
HCO3-(hydrogen carbonate).
There are five common classes of inorganic compounds:
 Binary ionic: These compounds contain one metal and one nonmetal,
example, KCl, AlCl3.
 Ternary Ionic: These compounds contain 3 elements with at least one
metal, one nonmetal, example, KNO3, Al(NO3)2
 Binary Molecular: These compounds contain two elements that are
both nonmetals, example, H2O, NH3
 Binary Acids: Aqueous solution of compound containing hydrogen
and other nonmetal. Formulas of acids begin with H, example, HCl (aq)
, H2S(aq)
 Ternary Oxyacids: Aqueous solution of a compound containing H, a
nonmetal, and oxygen, example, HNO3(aq), H2SO4(aq)
Aqueous solution is produced when a compound dissolves in H2O.
Chart showing different groups of Inorganic compound.
Inorganic Compounds
And Acids
Ionic Compounds
Binary Ionic Compound
Ternary Ionic Compound
Aqueous Acids
Binary Molecular Compound
Binary Acid
Ternary Oxy
Acids
CLASSIFICATION OF IONS
A positive ion is called CATION while a negative ion is called
ANION.
A single atom bearing positive or negative charge is called MONOATOMIC
ION, example, Cl-, Mg2+.
A group of atoms bound together and having overall positive or
negative charge is called POLYATOMIC ION, example, SO42-, CO32-.
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MONOATOMIC IONS
The names of most monoatomic cations are derived from parent
metal; for example, the sodium ion, Na+. Cations having two possible ionic
charges (transition metals) require further identification. The ionic charge
may be indicated using either the Stock system or the Latin system. The
stock system indicates the charge on the metal with Roman numerals in
parenthesis. The Latin system attaches the suffix –ous or –ic to the Latin
name of the element. Thus, Cu2+ is named copper (II) ion according to stock
system, and cupric ion using Latin system.
The names of monoatomic anions are derived from parent nonmetal.
A monoatomic anion is named using the nonmetal stem and attaching the
suffix –ide, example, Cl-, chloride ion
O2-, oxide ion.
POLYATOMIC IONS
Polyatomic anions generally contain one or more elements combined
with oxygen- Oxyanions.
Their names end –ate and –ite, example,
SO42- sulfate ion
SO32- sulfite ion ( this group have one less oxygen than –ate group)
ClO3- chlorate ion
ClO2- chlorite ion
An exception group exists with suffix –ide
CN- cyanide ion
OH- hydroxide ion
NH4+ ammonium ion
CATION
NH4+
COMMON POLYATOMIC IONS
IUPAC NAME
ammonium ion
ANION
IUPAC NAME
ANION
IUPAC NAME
C2H3O2CO32ClO3ClO2CrO42CN-
Acetate ion
OHClONO3NO2ClO4MnO4-
Hydroxide ion
Carbonate ion
Chlorate ion
Chlorite ion
Chromate ion
Cyanide ion
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hypochlorite ion
Nitrate ion
Nitrite ion
Perchlorate ion
Permanganate ion
Cr2O72HCO3HSO4-
Dichromate ion
PO43SO42SO32-
Hydrogen carbonate ion
Hydrogen sulfate ion
Phosphate ion
sulfate ion
Sulfite ion
WRITING CHEMICAL FORMULAS
An ionic compound is composed of positive and negative ions. A
formula unit is the simplest representative particle in an ionic compound.
A formula unit is neutral, therefore the total number of positive ions(from
metals) is equal to the total number of negative ions ( from nonmetals) in
both formula unit and ionic compound. Examples,
Na+ + ClNaCl
2+
Ca + 2ClCaCl2
3+
Al + 3ClAlCl3
4+
2Pb + 2O
PbO2
Formulas Containing Polyatomic Ions
2K+ + SO42K2SO4
+
2NH4 +SO4
(NH4)2SO4
BINARY IONIC COMPOUND
Ionic compounds have overall charge of zero, even though it contains
charged ions from the metal(positive ion) and nonmetals(negative ions).
Fe
O
X
this gives, Fe2O3
3
2
Co
N
X
this gives, CoN
3
3
When writing a chemical formula, the positive cation is always written
before the negative anion.
MgO- magnesium oxide
PREDICTING FORMULAS OF BINARY IONIC COMPOUND
Formula for NaCl: All alkali metal chlorides have similar formula for
their chlorides- LiCl, KCl.
For alkaline earth metals: If BaCl2 is the chloride formed, then MgCl2, CaCl2
and SrCl2 will also follow this pattern.
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TERNARY IONIC COMPOUND
A compound containing a metal and two other elements are classified
as ternary ionic compound. It comprises of a monoatomic metal cation and a
polyatomic oxyanion, example, NaNO3.
The names of ternary ionic compounds usually have the suffix –ate or –ite.
Example, KClO3 Potassium Chlorate
KClO2 Potassium Chlorite
If you have a transition metal, the charge needs to be determined first.
BINARY MOLECULAR COMPOUNDS
Binary molecular compound is composed of 2 nonmetals. A molecule
is the simplest representative particle in a binary molecular compound.
The following order is prescribed by IUPAC for writing the elements in a
compound.
C, P, N, H, S, I, Br, Cl, O, F
Examples of binary compounds with hydrogen are as follows:
CH4, PH3, NH3, H2S, HI, HBr, HCl, H2O and HF
NAMING BINARY MOLECULAR COMPOUNDS
 First element in the compound be named first
 The second element bears the suffix –ide.
 The number of atoms of each element be indicated by Greek prefixes
in the table below
Atom
Prefix
Atom
Prefix
1
-mono
6
-hexa
2
-di
7
-hepta
3
-tri
8
-octa
4
-tetra
9
-nona
5
-penta
10
-deca
When you have two vowels in the name of a compound, the first
vowel is dropped, examples,
Monooxide, you write monoxide
Tetraoxide, you write tetroxide.
BINARY ACIDS
Binary acids are aqueous solutions of compounds containing
hydrogen and a nonmetal. A binary acid is produced by dissolving a binary
molecular compound in water. Example, HF and HCl.
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First, use the prefix hydro before the nonmetal stem.
Next, add the suffix –ic acid.
Example, HCl(aq)------ Hydro + Chlor + ic acid = Hydrochloric acid
H2S(aq) ------ Hydro + Sulfur + ic acid = Hydrosulfuric acid
TERNARY OXYACIDS
Ternary oxyacids are aqueous solution of a compound containing
hydrogen and oxyanion.
Naming method is by attaching the suffix –ic acid to the nonmetal stem of
the oxyanion.
Examples, HNO3(aq) ----- Nitric acid
HNO2(aq) ------Nitrous acid
Ternary Oxyacids
Sulfuric acid, H2SO4(aq)
Sulfurous acid, H2SO3(aq)
Polyatomic Oxyanion
Sulfate ion, SO42Sulfite ion, SO32-
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