Writing Ionic Formulas
Puzzle Project.
In an ionic bond, a
positively charged
“Cation” combines
with a negatively
charged “Anion”
Formation of Cations
Cations form when an atom
loses one or more electrons
to form a positively charged
ion. In this example a
Sodium atom is losing one
electron to form a sodium
cation with a 1+ charge..
Formation of anions
Anions form when atoms
gain one or more electrons.
In this example, a Chlorine
atom is gaining one electron
to form the Chloride (notice
the name change) anion
with a 1- charge.
+
Sodium metal
(explodes on contact
with water)
Chlorine gas
(Poison-mustard gas in
World War I)
Combine to make
Sodium
Chloride.
Table
Salt!
Which tastes
really good on
french fries!
The trick to writing the ionic
formulas is that you need to
make it so that the charges on
all of the ions in the formula
add up to zero.
Here are some puzzle pieces to help with writing ionic formulas.
Na1+
F1-
Cl1-
O2-
Al3+
Ca2+
S2P3Be2+
Li1+
Mg2+
I1-
N3-
Lets see how the
puzzle pieces can
be used to write
an ionic formula.
For Sodium Chloride, we
will need Sodium ions
and Chloride ions.
We will need Na1+ and Cl1-
We will need Na1+ and Cl1-
Na1+
Cl1-
Do the puzzle
pieces fit
together?
Sodium Chloride contains one Sodium ion
and one Chloride ion. The formula is NaCl
1 x Na1+= 1+
1 x Cl1- = 1-
1-1=0
Lets try one
more!
Sodium Oxide
contains Sodium
ions and Oxide
ions.
We will need Na1+ and O2-
We will need Na1+ and O2-
Na1+
O2-
Lets see if it
works.
Na1+
O2-
We can bring in
1+
one more Na
ion.
Na1+
O2-
Na1+
Lets try
again.
Sodium Oxide contains two Sodium ions and
one Oxide ion. The formula is Na2O
2 x Na1+=2+
1 x O2- = 2-
2-2=0
In the Ionic Compound Puzzle Piece
Project, you will create a slide
presentation where you use the
puzzle pieces to determine the ionic
formula of a compound. You will
also provide information about the
use of the compound.
Sodium Chloride
Sodium Chloride contains
one sodium ion and one
chloride ion. The formula is
NaCl
Sodium Chloride is used as a
flavor enhancer for foods
such as french fries.
Na1+
Cl1-
Sodium Oxide
Sodium Oxide contains 2
Sodium ions and one
Chloride ion. The formula is
Na2O.
Sodium Oxide is used as a
glaze in ceramics.
Na1+
O2Na1+
Even in difficult times it is possible
to have fun!