C2
Unit 1
Bonding
Learning Outcomes
By the end of the lesson you ……be able to:
Must (Grade E/F): State what ionic bonding is.
Should (Grade C/D):
Could (Grade B/C):
Starter
What are the chemical symbols for:
Calcium
Oxygen
Sodium
Iron
Copper
Carbon
What is a compound?
• A substance formed when two or more
elements chemically combine.
• Can you give any examples?
What do we mean by chemically
combined?
• Involves either transferring or sharing of
electrons in the highest occupied energy
levels (shells) of atoms in order to achieve
the electronic structure of a noble gas.
Full electron shells
Each shell has a maximum number of electrons that it can
hold. Electrons will fill the shells nearest the nucleus first.
1st shell holds
a maximum of
2 electrons
2nd shell holds
a maximum of
8 electrons
3rd shell holds
a maximum of
8 electrons
Atoms of noble gases have completely full outer shells.
This makes them very unreactive or stable.
Ions
An ion is formed when an atom gains or loses electrons and
becomes charged:
+
-
The electron is negatively charged
The proton is positively charged
If we “take away” the electron
we’re left with just a positive
charge:
This is called an ion.
+
+
Example Ions
Cations
Sodium – Na+
Magnesium – Mg2+
Iron – Fe3+
Copper – Cu2+
Anions
Chloride – ClSulphate – SO42Carbonate – CO32Oxide – O2Hydroxide - OHAll compounds have no overall
charge. Can you therefore write
down the formula of:
1.
2.
3.
4.
5.
Sodium chloride
Magnesium chloride
Copper oxide
Iron Oxide (Kind of tricky!)
Barium Hydroxide (Very tricky!)
How to represent ionic bonding
in an exam.
This is called an electrostatic
attraction.
Ionic compounds have high
melting points because of this
attraction.
To melt this compound you would
require a temperature of 801
degrees celcius.
Now apply knowledge to
worksheet.
TRUE OR FALSE
Answer the following questions T or F:
T
1. An ion is formed when an atom gains or losses
electrons.
F
2. An example of a cation is sulphate SO42-.
3. A positive metal ion is formed when electrons are lost
from the metal atom.
T
4. Ionic bonding is between a positive metal ion called a
cation and a negative non-metal ion called an anion. It
is the electrostatic attraction between these two ions.
5. Properties of ionic compounds are that they have low
melting points, non-conductors of electricity when
molten.
F
T
Common ions bingo
Group 1 – The Alkali Metals
• Watch the demo.
• Write down your observations.
• Write down the chemical reactions (word
and symbol)
Group 7 – The Halogens
Group 1 and 7 elements react
with each other.
• Can you explain why?
Practical: Making ionic compounds
Substance
Appearance Before
Appearance after
Magnesium
Copper
Iron
Calcium reacts with oxygen in air to form calcium oxide.
Calcium + oxygen → calcium oxide
Ca
+
O2
→ CaO
Write the word and symbol equations for what is formed with the
elements above.
Aluminium Oxide Structure