Learning outcomes:
1 I can describe the properties of ionic compounds.
2 I can name chemical formulas and write chemical formulas using only names.
3.2 Ionic compounds




A metal (+ ion) and a non-metal (- ion)
Ions are opposites and of course…opposites attract.
They are all solids at room temperature
When dissolved in water, conducts electricity. (this led to the
invention of batteries)
 They have a distinct crystal shape.
 High melting point.
 When dissolved in water, it forms a solution of ions.
Ex:
Hydrogen
Ion charge = 1+
ion Notation = H+
Oxygen
Ion charge = 2 -
ion Notation = O2-
Table of Ion charge
Element
Copper
Lead
Aluminum
Sodium
Ion Charge
Ion Notation


+
-
A superscript ( + ) or a ( – ) are used to indicate the charge. Na and Cl
Some ions can also form when certain atoms of elements combine. These ions are
called polyatomic
ions (poly meaning
“many”). Polyatomic
atoms are a group of
atoms acting as one.
Example:
1 carbon
atom reacting with 3
oxygen atoms
produces 1
carbonate group of
atoms, which act as
one. CO3
2-
Then, when
carbonate ions react
with calcium atoms
they produce
calcium carbonate,
or limestone. Ca CO3
2-
http://www.youtube.com/watch?v=vscoYh6m46M
Writing the formula of a compound using its name is a 5 step process.
Sodium Chloride
1. Write the Symbols
Na
Cl
2. Write the charges (use the periodic table to find them)
Na 1+
Cl 1-
3. Cross over the charges from top to bottom.
Na 1+
Cl 1-
Na1-
Cl1+
4. Eliminate the charges.
Na1
Cl1
5. Simplify the numbers and
eliminate the 1’s
NaCl
Table of formulas – I want to see the 5 steps
Potassium Oxide
Magnesium
phosphoride
Lithium floride
Aluminum chloride
Naming Ionic Compounds in a 5 step process
Two rules:
1. The chemical name of the
metal or positive ion goes first,
followed by the name of the nonmetal or negative ion.
2. The name of the non-metal
negative ion changes its ending to
ide.
NB: one exception – Where negative ions
are polyatomic ions, the name remains unchanged.
Some elements with more than one ion charge use a roman numeral in its
chemical name to clearly show which ion is being used. Cu(II)SO4 (Copper
II Sulfate)
H2S
LiH
FeS
CaCO3
Caricature analysis
1. What is the subject?
2. What conclusion can be made with this caricature?
3. What inference can be made with this caricature?
Answer questions 1, 2, 3, 6, 7, 8 from page 149
Worksheet