Ionic Bonding Worksheet
How create the Lewis Structure (Dot Diagram) of an
atom. (Problems 1-8)
Example: Draw the Lewis Structure of a Magnesium Atom.
1.
Find the atomic number of that element by locating that element using the
periodic table. The atomic number tells us the number of total protons,
electrons, and neutrons in the atom.
Mg has an atomic number of 12.
Mg has 12 TOTAL electrons
2.
Find the number of valence electrons. Remember that atomic masses tell us
the number of electrons, but NOT the number of VALENCE electrons.
Valence electrons are the electrons in the outermost energy level, that
determine if the element forms a chemical bond or not.
There can be 2 electrons in the innermost energy level of the atom
There can be 8 electrons in each of the energy levels after the 1 st one.
Magnesium
Atomic
Number
Atomic
Mass
Number of
Protons,
electrons,
and
neutrons
Column in
the periodic
table
Number of
valence
electrons
12
24.305
amus
12
2
2
Mg has 2 valence electrons because it has 12 total electrons. 2 of those occupy the 1 st energy
level, and 8 of them occupy the 2nd energy level. Therefore there are 2 electrons left over in the 3 rd
energy level.
Shortcut- Mg has 2 valence electrons because it is in the 2 nd column.
3.
Draw the Lewis structure, by writing down the atomic symbol. Then place each valence electron
around the symbol as a dot. Place one at each of the 4 sides of the symbol, then double them up.
The most valence electrons that an element can have would be 8 and the least would be 1 valence
electron.
BAD
GOOD
Lewis Structures of Atoms: Draw Lewis Structures for the following elements.
1. Cl
5. S
2. H
6. Ca
3. O
7. F
4. Ar
8. Na
How to Convert an atom into an ION. (Problems 9-14)
Example: What does a Chlorine Ion look like?
1.
2.
Draw the lewis structure of a chlorine atom.
Follow the octet rule. Atoms are unstable until the have a full
outer shell of electrons. For H and He, this means that they have 2
electrons. Form all other elements, this means that they have 8.
For this reason, Noble Gasses do NOT form ions.
Atom
Ion
F
-
Ca
2+
S
2-
Ne
Does not
form an
ion
If chlorine gains just 1 electron, it will have 8 electrons in its outer shell. So add 1 electron to the
chlorine atom.
3.
Remember that the charge of an electron is negative. So if we gain 1 electron our atom gets a
negative charge. All negatively charged ions are called anions. Write the ion’s charge in the
upper right hand side of the lewis structure.
4.
If an ion loses electrons to have 8 electrons in its outer shell, it loses negative charges. This makes
the atom positively charged. Positively charged ion are called cations. See the steps below for
making a sodium cation.
Lewis Structures of Ions: Draw Lewis Structures for the following IONS. (one of them doesn’t form an
ion)
1. Cl
2. H
5. S
6. Ca
3. O
4. Ar
7. F
8. Na
How to draw Lewis Structures of Ionic Compounds
(Problems 15-20)
Example: What does a molecule would form from Sodium ions and chlorine ions?
1.
Draw the lewis structure of a chlorine atom and a sodium atom.
2.
Convert the atoms to ions. But…
Electrons can’t just come from nowhere (that would violate the 1 st law of Thermodynamics!). So
when sodium loses an ion it must be transferred to the chlorine.
Draw the process of moving electrons from one atom to the other.
3.
Re-draw the lewis structure of the combined molecule. Include the charge of each ion.
4.
Sometimes this can be a little more difficult. Think of bonding aluminum to oxygen. Aluminum
wants to get rid of 3 electrons, but oxygen can only take 2.
Therefore, the last remaining electron must go to another oxygen atom. But this atom is still short
1 electron.
In order to make the oxygen have a full octet lets take an electron away from a second Aluminum
atom.
In order to make the aluminum have a full octet, it would have to lose another 2 electrons, so lets
add another oxygen atom
Now all 3 oxygen atoms have full octets and both aluminum atoms have full octets. Redraw the
ionic compound to make everything look neat. Add in charges.
Ionic Bonding: Draw the lewis structures of the following ionic compounds.
15.
Potassium and chlorine
16.
oxygen and aluminum
17.
magnesium and fluorine
18.
Bromine and Calcium
19.
Lithium and Sulfur
How to write the chemical formula of an ionic
compound(Problems 20-24)
Example:
Write the compound made from fluorine and magnesium
1. Draw the lewis structure of the compound that a fluorine atom and
a magnesium atom make.
Metal
Compound
Na
Nonmetal
Cl
Al
O
Al2O3
Mg
F
MgF2
NaCl
2.
Ionic compounds are made when metals
and non-metal bond together. Identify the
metal and and non-metal using the
periodic table
3.
Write the atomic symbols of the two elements. The metal always goes first.
4.
Since there are 2 fluorine ions in one molecule of this compound, add a “2” subscript after the F.
Naming ionic compounds: name the following ionic compounds
20.
Potassium and chlorine
Answer______________
21.
oxygen and aluminum
Answer______________
22.
magnesium and fluorine
Answer______________
23.
Bromine and Calcium
Answer______________
24.
Lithium and Sulfur
Answer______________
How to name ionic compounds(Problems 25-29)
Example: Name the compound made from chlorine and sodium.
1. Draw the lewis structure of the compound that a chlorine atom and a sodium atom make.
2.
Write the chemical formula of the compound that they make.
NaCl
3.
The first part of the name is just the metal.
Sodium
4.
The second part of the name is the nonmetal
Sodium chlorine
5.
Take away the last syllable of the non-metal and replace it with the “–ide” suffix.
Sodium chloride
Naming ionic compounds: name the following ionic compounds
25.
Potassium and chlorine
Answer______________
26.
oxygen and aluminum
Answer______________
27.
magnesium and fluorine
Answer______________
28.
Bromine and Calcium
Answer______________
29.
Lithium and Sulfur
Answer______________