Name:
Ionic Bonding
Year 11 Science
Ruawai College 2014
Ions and Ionic Compounds
Ions are atoms that have gained or lost electrons. Ions that lose electrons form
positive ions. Ions that gain electrons form negative ions.
Sodium loses an electron to achieve a full shell.
Chlorine gains an electron to achieve a full shell.
But the electrons do not just come and go from nowhere. Electrons are
transferred from one atom to another when ions are formed.
The electron that sodium loses is the same electron that chlorine gains. When
this happens a strong bond is formed between the two atoms – an ionic bond.
A strong ionic bond forms between the positive sodium ion and the negative
chloride ion.
This strong bond holds the two ions in a regular arrangement.
Above is a 2D model of the salt sodium chloride. For every positive sodium ion
there is a negative chloride ion.
Sodium chloride is made up of Na+ and Cl- in a ratio of 1:1. We write sodium
chloride as NaCl. NaCl is the formula for sodium chloride.
Above is a 3D model of sodium chloride showing the lattice arrangement.
Key Questions:
Above is a diagram of magnesium oxide being formed when electrons are
transferred from one atom to another atom.
1.
How many electrons are being transferred from the magnesium atom to
the oxygen atom?
2.
What does the magnesium atom change into when it loses two
electrons?
3.
What does the oxygen atom change into when it gains two electrons?
4.
What forms between the two ions when electrons are transferred from
one to the other?
5.
What is the chemical formula of magnesium oxide?
6.
Draw a 2D model of magnesium oxide?
.
A 3D model of Lithium chloride is shown above.
7.
What is ratio of lithium ions to chloride ions?
8.
What is the formula of lithium chloride?
A 3D model of Potassium chloride is shown above.
9.
What is ratio of potassium ions to chloride ions?
10.
What is the formula of potassium chloride?
Exercises:
Above is a diagram of magnesium chloride being formed when electrons are
transferred from one atom to two other atoms.
11.
How many electrons are being transferred from the magnesium atom to
each chloride atom?
12.
What does the magnesium atom change into when it loses two
electrons?
13.
What do the chlorine atoms change into when they gain an electron?
14.
What forms between the magnesium ion and the two chloride ions
when electrons are transferred?
15.
The chemical formula of magnesium chloride is MgCl2. What does the 2
indicate?
16.
The ratio of magnesium ions to chloride ions is 1:2. Why is the ratio 1:2?
Chemical Formulas and Names of Ionic Compounds
The diagrams below show some models of ionic compounds.
a.
Sodium chloride
Chemical
formula:
NaCl
b.
Calcium chloride
Chemical
formula:
CaCl2
c.
Aluminium oxide
Chemical
formula:
Al2O3
Key Questions:
1.
What are the names of the elements found in the compounds above:
a.
b.
c.
2.
How does the name of the elements in each compound differ from that
of the free elements.
3.
How many sodium ions are there in the sodium chloride sample shown
above?
How many chloride ions?
What is the ratio between the two?
4.
How many calcium ions are there in the calcium chloride sample shown
above?
How many chloride ions?
What is the ratio between the two?
5.
How many aluminium ions are there in the aluminium oxide sample
shown above?
How many oxide ions?
What is the ratio between the two?
6.
What is the relationship between the chemical formula for the
compounds above and the ratio of the ions between them?
7.
What is the charge on the sodium ion?
What is the charge on the chloride ion?
8.
What is the charge on the calcium ion?
What is the charge on the chloride ion?
What is the charge on the oxide ion?
10.
All samples of sodium chloride have a ratio of one sodium ion for one
chloride ion. What must be true of the total charge for any sample of
sodium chloride?
11.
All samples of calcium chloride have a ratio of one calcium ion for two
chloride ions. What must be true of the total charge for any sample of
calcium chloride?
12.
All samples of aluminium oxide have a ratio of two aluminiums for three
oxide ions. What must be true of the total charge for any sample of
aluminium oxide?
13
From the pattern seen in the last three questions, what is the rule for
the total charge for a compound?
Exercise:
14.
Write the name of the compound above.
15.
Write the chemical formula of the compound above.
Ionic Charges
Some ions are listed in the table below:
Group
1
2
13
15
16
17
Charge
+1
+2
+3
-3
-2
-1
Oxide
O2Sulfide
S2-
Fluoride
FChloride
Cl-
Lithium
Nitride
+
Li
N3Sodium Magnesium Aluminium Phosphide
Na+
Mg2+
Al3+
P3Potassium
Calcium
+
K
Ca2+
Key Question
16. What patterns do you notice about the charges on the ions and their
position on the periodic table.
Exercise
17. Write the correct chemical formula for each of the following
compounds.
a.
Compound
Lithium chloride
b.
Potassium chloride
c.
Sodium fluoride
d.
Calcium oxide
e.
Magnesium sulfide
f.
Magnesium chloride
g.
Calcium chloride
h.
Aluminium chloride
i.
Aluminium fluoride
j.
Aluminium oxide
Formula
Name:
Ionic Bonding
Year 11 Science
Ruawai College 2014
Ions and Ionic Compounds
Ions are atoms that have gained or lost electrons. Ions that lose electrons form
positive ions. Ions that gain electrons form negative ions.
Sodium loses an electron to achieve a full shell.
Chlorine gains an electron to achieve a full shell.
But the electrons do not just come and go from nowhere. Electrons are
transferred from one atom to another when ions are formed.
The electron that sodium loses is the same electron that chlorine gains. When
this happens a strong bond is formed between the two atoms – an ionic bond.
A strong ionic bond forms between the positive sodium ion and the negative
chloride ion.
This strong bond holds the two ions in a regular arrangement.
Above is a 2D model of the salt sodium chloride. For every positive sodium ion
there is a negative chloride ion.
Sodium chloride is made up of Na+ and Cl- in a ratio of 1:1. We write sodium
chloride as NaCl. NaCl is the formula for sodium chloride.
Above is a 3D model of sodium chloride showing the lattice arrangement.
Key Questions:
Above is a diagram of magnesium oxide being formed when electrons are
transferred from one atom to another.
1.
How many electrons are being transferred from the magnesium atom to
the oxygen atom?
2
2.
What does the magnesium atom change into when it loses two
electrons?
Magnesium ion Mg2+
3.
What does the oxygen atom change into when it gains two electrons?
Oxide ion O2What forms between the two ions when electrons are transferred from
one to the other?
Ionic bond
What is the chemical formula of magnesium oxide?
MgO
Draw a 2D model of magnesium oxide?
4.
5.
6.
.
A 3D model of Lithium chloride is shown above.
7.
8.
What is ratio of lithium ions to chloride ions?
1:1
What is the formula of lithium chloride?
LiCl
A 3D model of Potassium chloride is shown above.
9.
10.
What is ratio of potassium ions to chloride ions?
1:1
What is the formula of potassium chloride?
KCl
Exercises:
Above is a diagram of magnesium chloride being formed when electrons are
transferred from one atom to two other atoms.
11.
12.
13.
14.
15.
How many electrons are being transferred from the magnesium atom to
each chloride atom?
One electron to each chloride ion
What does the magnesium atom change into when it loses two
electrons?
Magnesium ion Mg2+
What do the chlorine atoms change into when they gain an electron?
Chloride ion ClWhat forms between the magnesium ion and the two chloride ions
when electrons are transferred?
Ionic bond
The chemical formula of magnesium chloride is MgCl2. What does the 2
indicate?
There are two chloride ions for every magnesium ion
16.
The ratio of magnesium ions to chloride ions is 1:2. Why is the ratio 1:2?
Two negative chlorides are needed to balance out the charge on
the one positive magnesium ion
Chemical Formulas and Names of Ionic Compounds
The diagrams below show some models of ionic compounds.
a.
Sodium chloride
Chemical
formula:
NaCl
b.
Calcium chloride
Chemical
formula:
CaCl2
c.
Aluminium oxide
Chemical
formula:
Al2O3
Key Questions:
1.
What are the names of the elements found in the compounds above:
a.
sodium and chlorine
b.
calcium and chlorine
c.
aluminium and oxygen
2.
How does the name of the elements in each compound differ from that
of the free elements.
Metal name stays the same
Non-metal name ending changes from -ine to -ide
3.
How many sodium ions are there in the sodium chloride sample shown
above?
9
How many chloride ions?
9
What is the ratio between the two?
1:1
4.
How many calcium ions are there in the calcium chloride sample shown
above?
5
How many chloride ions?
10
What is the ratio between the two? 1:2
5.
How many aluminium ions are there in the aluminium oxide sample
shown above?
4
How many oxide ions?
6
What is the ratio between the two?
2:3
6.
What is the relationship between the chemical formula for the
compounds above and the ratio of the ions between them?
Chemical formula shows the ratio of ions
7.
What is the charge on the sodium ion?
+1
What is the charge on the chloride ion?
-1
8.
What is the charge on the calcium ion?
+2
What is the charge on the chloride ion?
-1
What is the charge on the oxide ion?
-2
10.
All samples of sodium chloride have a ratio of one sodium ion for one
chloride ion. What must be true of the total charge for any sample of
sodium chloride?
Neutral / No charge
11.
All samples of calcium chloride have a ratio of one calcium ion for two
chloride ions. What must be true of the total charge for any sample of
calcium chloride?
Neutral / No charge
12.
All samples of aluminium oxide have a ratio of two aluminiums for three
oxide ions. What must be true of the total charge for any sample of
aluminium oxide?
Neutral / No charge
13
From the pattern seen in the last three questions, what is the rule for
the total charge for a compound?
All ionic compounds are neutral, they have no charge
Exercise:
14.
Write the name of the compound above.
Barium iodide
15.
Write the chemical formula of the compound above.
BaI2
Ionic Charges
Some ions are listed in the table below:
Group
1
2
13
15
16
17
Charge
+1
+2
+3
-3
-2
-1
Oxide
O2Sulfide
S2-
Fluoride
FChloride
Cl-
Lithium
Nitride
+
Li
N3Sodium Magnesium Aluminium Phosphide
Na+
Mg2+
Al3+
P3Potassium
Calcium
+
K
Ca2+
Key Question
16. What patterns do you notice about the charges on the ions and their
position on the periodic table.
All ions in a group have the same charge
Exercise
17. Write the correct chemical formula for each of the following
compounds.
a.
Compound
Lithium chloride
Formula
LiCl
b.
Potassium chloride
KCl
c.
Sodium fluoride
NaF
d.
Calcium oxide
CaO
e.
Magnesium sulfide
MgS
f.
Magnesium chloride
MgCl2
g.
Calcium chloride
CaCl2
h.
Aluminium chloride
AlCl3
i.
Aluminium fluoride
AlF3
j.
Aluminium oxide
Al2O3