Ionic
Compounds
Lewis Dot Diagrams
Chemical Interactions Occur between
the Valence Electrons
Dots: represent valence
electrons
When atoms
combine to
make
molecules,
they form
chemical
bonds.
Valence electron
interaction
• Octet Rule
Atoms will
form bonds
by:
Forming Chemical
Bonds
– Sharing
– Giving or
– Taking
electrons to
complete
their octet
Higher energy farther away from nucleus
Atoms form ions to have stable
electron configurations (similar
to noble gases)
hh
Ionic Bonds
• Ionic Bonds form when one atom
(nonmetal) gains electrons and the other
atom (metal) loses electrons in order to
gain stability.
• Ionic Bonds form between a metal
(cation) and a nonmetal (anion).
To form an ion, lithium will most
likely:
Gain 1 electron
Gain 2 electrons
Lose 1 electron
Lose 2 electrons
91%
3
4
5%
0%
2
5%
1
1.
2.
3.
4.
Forming Chemical Bonds
• Lithium
–Better to lose 1 electron or
to gain 7 electrons?
X
Therefore, as an ion lithium will
have what charge?
73%
27%
4
0%
3
0%
2
1+
2+
12-
1
1.
2.
3.
4.
Ionic Bonds
• Atoms gain or lose its
electrons
+
NaCl salt
Chemical Interactions
Occur between the
Valence Electrons
Lewis structures are
simpler to do & see
Formation of MgCl2
Formation of Na2S
• Write down the chemical formula for
Aluminum Flouride
Formation of AlF3
Today is a practice Day!
• We need to be able to name ions given
chemical formula
• We need to be able to determine the
chemical formula given the name
Valence Electrons  Noble Gas Structure = Octet
1,2
3,4,5,6,7,8
IONIC BONDS / Cations and Anions
Cation – positive ions
Transition Metals use
Roman Numerals to tell you the ox #
Anion – negative ions
Oxidation Numbers
• Oxidation Numbers
- indicated # of e’
lost, gained or
shared.
Ex. Oxidation number
of chlorine is -1
Halogens will have an oxidation
number of:
0%
0%
-2
0%
2
0%
-1
+1
+2
-1
-2
1
1.
2.
3.
4.
Alkaline earth metals will have
an oxidation number of:
0%
0%
-2
0%
2
0%
-1
+1
+2
-1
-2
1
1.
2.
3.
4.
We will name binary
compounds together
• Using pages 156- 158
• Describe how to name cations
and anions when they are by
themselves
Naming Binary Ionic
Compounds
• Write the name of
the ionic
compound, Ca2N3.
• Write the name of
the ionic
compound, K2O.
What is the name of BeBr2?
Boron bromine
Beryllium bromine
Bromide beryllide
Beryllium bromide
Beryllide bromide
m
lid
e
br
o
liu
m
0%
br
om
...
...
0%
l..
.
Be
ry
l
id
e
Br
om
liu
m
ry
l
Be
be
br
o
ry
l
m
in
e
m
br
o
n
0%
Be
ry
l
0%
...
0%
Bo
ro
1.
2.
3.
4.
5.
Metals with Variable Charges
• Many transition metals can form more than
one type of cation.
• For this reason, you must show the
oxidation number in the name using
Roman Numerals
Naming Binary Ionic
Compounds with Transition
Metal Cations
• Write the name of
the ionic
compound, Cu2O..
• Write the name of
the ionic
compound, NiS.
What is the name for SnBr2?
Bromide Tin
Tin Bromide
Tin (I) Bromide
Tin (II) Bromide
Tin (III) Bromide
Tin (IV) Bromide
0%
0%
0%
0%
0%
Br
om
id
Ti
e
n
(I)
Br
om
id
Ti
. ..
n
(II
)B
ro
m
i..
Ti
.
n
(II
I)
Br
om
Ti
. ..
n
(IV
)B
ro
m
i..
.
n
Ti
id
e
Ti
n
0%
Br
om
1.
2.
3.
4.
5.
6.
What is the name for FeI3?
Iron iodide
Iron (I) iodide
Iron (II) iodide
Iron (III) iodide
(I I
I)
i
Iro
n
(I I
)i
od
io
(I )
Iro
n
Iro
n
di
d
di
de
io
0%
od
...
0%
i..
.
0%
...
0%
Iro
n
1.
2.
3.
4.
What is the name for MnS?
Manganese sulfide
Manganese (I) sulfide
Manganese (II) sulfide
Manganese (III) sulfide
0%
II I
...
0%
e(
ne
s
M
an
ga
M
an
ga
ne
se
(II
(I)
.. .
)..
.
0%
ne
se
an
ga
M
an
ga
ne
se
su
lf.
..
0%
M
1.
2.
3.
4.
Exceptions:
• Some of the transition metals
have only one ionic charge:
–Do not need to use roman
numerals for these:
–Silver is always 1+ (Ag1+)
–Cadmium and Zinc are always
2+ (Cd2+ and Zn2+)
Writing Formulas for Binary
Ionic Compounds
• Write the formula
for barium iodide.
• Write the formula
for sodium oxide.
• Write the formula
for aluminum
nitride.
• Write the formula
for copper (I)
sulfide.
Criss-Cross Method for
Writing Formulas
- You can write the oxidation
number and criss-cross them
3+
Al 2
as subscripts.
2S
- Note – if not in lowest terms
= Al2S3
you must reduce the subscripts
(ex. Magnesium oxide)
3
What is the formula for
aluminum bromide?
AlBr
AlBr2
Al3Br
Br3Al
AlBr3
r3
0%
Al
B
0%
Br
3A
l
0%
Al
3B
r
r2
0%
Al
B
r
0%
Al
B
1.
2.
3.
4.
5.
What is the formula for
magnesium oxide?
MgO
Mg2O2
MgO2
Mg2O
OMg
g
0%
OM
M
M
0%
g2
O
0%
gO
2
0%
M
g2
O2
gO
0%
M
1.
2.
3.
4.
5.
Write the formula for titanium (II)
chloride.
TiCl
Ti2Cl
TiCl2
Ti2Cl2
2C
l2
0%
Ti
Cl
2
0%
Ti
2C
l
0%
Ti
Cl
0%
Ti
1.
2.
3.
4.
Write the formula for tin (IV)
oxide.
SnO
SnO4
SnO2
Sn4O
Sn2O
0%
Sn
2O
2
0%
Sn
4O
Sn
O
0%
Sn
O
0%
4
0%
Sn
O
1.
2.
3.
4.
5.
POLYATOMIC IONS
• Not all compounds are made of only 2
types of atoms
• poly – “many”
Memorize the polyatomic ions from p. 170.
Tricks for Polyatomic Naming
Perchlorate
chlorate
chlorite
Hypochlorite
per+root+ate
root+ate
root+ite
hypo+root+ite
ClO4-1
ClO3-1
ClO2-1
ClO-1
Prefixes and suffixes designate number of
oxygens
Naming Polyatomic Ionic
Compounds
• Polyatomic ionic compounds are named
just like binary ionic compounds.
• Exception: be sure to enclose the
polyatomic ion in parentheses before
writing the subscript (only necessary if
subscript is not 1).
• Ex. Barium hydroxide = Ba(OH)2
Write the formula for Calcium
Nitrate.
CaNO2
Ca(NO2)2
Ca2NO3
Ca2NO2
Ca(NO3)2
0%
Ca
(
NO
3)
2
0%
Ca
2N
O2
0%
Ca
2N
O3
NO
2)
2
0%
Ca
(
O2
0%
Ca
N
1.
2.
3.
4.
5.
Write the formula for
Magnesium Phosphate.
MgPO4
Mg3(PO4)2
Mg4(PO3)2
MgPO3
Mg(PO4)2
0%
O4
)2
g(
P
M
gP
O
3
0%
M
O3
)2
0%
M
g4
(P
O4
)2
0%
M
g3
(P
gP
O
4
0%
M
1.
2.
3.
4.
5.
Naming Ionic Compounds