This document provides information on binary compounds and ionic compounds containing polyatomic ions. It defines binary compounds as those containing only two elements and ionic binary compounds as those where one element is a metal and the other is a non-metal. Rules are provided for naming ionic compounds containing metals and non-metals or polyatomic ions. Key points include that polyatomic ions are charged groups that don't occur alone and ionic compounds contain positive and negative ions to be neutral overall. Formulas show how to write names and formulas for ionic compounds containing polyatomic ions.

3. Binary Compound
A compound in which
only 2 elements are
present
NaCl, CO2, NH3, and
P4O10
Binary Ionic Compound
An Ionic compound in
which one element
present is a metal and
the other element
present is non-metal
NaCl
Metal
Non-Metal

4. Which of the following binary compounds would
be expected to be an ionic compound?
Al2S3 CO2
H2O MgCl2
KF PF3
NH3 Fe2O3
Ionic
Not Ionic
Ionic
Not Ionic
Not Ionic
Ionic
Ionic
Not Ionic

5.  Rule: The full name of the metallic element
is given first, followed by a separate word
containing the stem of the metallic non-
metallic element and the suffix –ide.
Metal
Non-Metal
potassium chloride
Note:
“chlor” is the stem
of the non-metallic
element chlorine

7. Name the following binary ioniccompounds
MgO Al2S3
K3N BeO
CaCl2 Li3P
Na2S BaI2
magnesium
oxide
potassium
nitride
calcium
chloride
sodium sulfide
aluminum
sulfide
berellium oxide
barium iodide
lithium
phosphide

8. What is Variable Ionic Behavior?
Pertains to the less predictable behavior of some
metals because they have the ability to form more
than one type of ion.(Ex. Fe2+ and Fe3+)
Note:
all inner transition elements, most transition metals, and
a few representative metals exhibit variable ionic charge
behavior.

9.  Rule: “The charge of the metal ion must be
included in the name.”
Ex. FeCl2 and
FeCl3
iron (II) chloride
iron (III) chloride

10.  Old Method: “Latin name is used + the suffix
–ic and –ous.” “ic” is used for ion of higher
charge, and “ous” for ion of lower charge.
FeCl2
ferric chloride
ferrous chloride
FeCl3

11.  Calculating for the charge of Metal Ion
Ionic charge must
add to zero
Ex. FeCl2
iron charge + 2 (chlorine charge) = 0
Iron charge + 2(-) = 0
Iron charge = 2+

13. Name the following compounds, which contain
on or more polyatomic ions
AuCl Fe2O3
PbO2 Cu2S
Gold (I)
chloride
Lead (IV) oxide
Iron (III) oxide
Copper (I)
sulfide

15. ION
Monatomic ion
“an ion formed from
a single atom
through loss or gain
of electrons.”
Ex. Cl-,Na+, Ca2+, N3-
Polyatomic Ion
“an ion formed from
a group of atoms
(held together by
covalent bonds)
through loss or gain
of electrons.”
Ex. NO3
-, SO4
2-, PO4
3-

17. MOLECULE
“group of two or more
atoms that functions as a
unit because the atoms
are tightly bound
together.”
“One of the fundamental
units forming a chemical
compound”
Molecules can
occur alone.
Polyatomic ions
don’t.

18. Polyatomic ions are
“charged pieces of a
compound”, not
compounds.
They are found
associated with ions
of opposite charge.
Ionic compounds require
presence of both positive
and negative ions and are
neutral overall.

20. 1. Most of the polyatomic ions have negative
charge, which can vary from -1 to -3. (except
NH4 (Ammonium) and H3O+ (hydronium))
2. 2 of the negatively charged polyatomic ions,
OH- (hydroxide) and CN- (cyanide) have
names ending in –ide.

21. 3. A number of –ate and –ite pairs of ions exist, as in
SO4
2- (sulfate) and SO3
2- (sulfite). The –ate ion
always has one more oxygen atom than the –ite
ion. Both the –ate and –ite ions carry the same
charge.
4. A number of pairs of ions exist wherein one
member of the pair differs from the other by having
a hydrogen atoms present, as in CO3
2- (carbonate)
and HCO3
- (hydrogen carbonate or bicarbonate).
In such pairs, the charge on the ion that contains
the hydrogen is always 1 less than that of the
other ion.

22. 1. When more than 1 polyatomic ion of a given kind is
required in a chemical formula, the polyatomic ion is
enclosed in parentheses, and a subscript, placed
outside the parentheses, is used to indicate the
number of polyatomic ions needed.
Fe(OH)3
Iron charge + 3(OH charge) = 0
Iron charge + 3(-1) = 0
Iron charge – 3 = 0
Iron charge = 3+
Iron (III) hydroxide

23. 2. So that the identity of polyatomic ions is
preserved, the same elemental symbol may
be used more than one in chemical
formula.
NH4NO3
Both NH4 and NO3 has Nitrogen
(N) as part of their components.
(Ammonium nitrate)

24. Determine the chemical formula for the ionic
compounds that contain these pair of ions.
Na+ and SO4
2- K+ and CO3
2-
Mg2+ and
NO3- Ca2+ and OH-
NH4
+ and CN- NH4
+ and
HPO4
2-
Na2SO4
Mg(NO3)2
NH4CN
K2CO3
Ca(OH)2
(NH4)2HPO4

25. Name the following compounds, which contain
one or more polyatomic ions
Ca3(PO4)2 Ba(NO3)2
Fe2(SO4)3 Cu3PO4
(NH4)2CO3 (NH4)2SO4
Calcium
phosphate
Iron (III)
sulfate
Ammonium
carbonate
Barium nitrate
Copper (I)
phosphate
Ammonium
sulfate

30.  General, Organic, and Biological Chemistry
by H. Stephen Stoker