Covalent bonding involves the sharing of electrons between non-metal atoms to achieve stable outer electron shells. A covalent bond is represented by a line or dot-cross diagram that shows the shared pair of electrons joining the atoms. Students learn to identify covalent compounds and draw Lewis dot-cross diagrams to represent covalent bonds between different elements including hydrogen, oxygen, nitrogen, and carbon.

1. Covalent bonding
Learning objectives:
1. How can I draw covalent bonds?
2. What are covalent bonds?

2. Starter - match these up!
• Carbon dioxide • Cl2
• Water • O2
• Chlorine
• CO2
• Oxygen
• CH4
• Methane
• H2
• Hydrogen
• H2O

3. Metals and Non-metals

4. Complete exam questions on the next slide.

5. 1. The diagram represents a particle of methane.
(a) What is the formula of methane?
..........................................................................(1)
(b) Choose a word from the box to answer the question.
Which of the words best describes the methane particle shown in the diagram?
(1)
atom ion molecule
(c) Choose a word from the box to answer the question.
What is the type of bonding shown in the diagram?
covalent ionic metallic (1)
(Total 3 marks)

6. Study and take notes
Find out what covalent bond is and how to
draw covalent bonds.

7. What is a covalent bond?
incomplete
Cl outer shells Cl
The two non-metal atoms cannot form a bond by transferring
electrons from one to another. Instead, they share
electrons.
Each atom now
Cl Cl has a
full, stable
outer shell.
The shared electrons join the atoms together. This is
called a covalent bond.

8. Drawing covalent bonds
A covalent bond is a shared pair of electrons.
Cl Cl
covalent bond
outer Cl – Cl
shell dot solid
–
Cl Cl
and cross line Cl Cl
diagram

9. Rules of Covalent bonding
o Needs 2 or more NON-METAL ATOMS
o Electrons are SHARED to complete the shells
o The electron shells overlap.

10. Drawing Molymods
To do:
Next practice drawing covalent bonds for
different molecules.

11. How many bonds?
1 2 3 4
What elements?
H O N C
Cl
• Hydrogen (H2) •Water (H2O)
• Chlorine (Cl2) •Methane (CH4)
• Hydrogen chloride (HCl) •Ammonia (NH3)
EXTENSION – draw O2 and CO2

12. Plenary – Ionic or Covalent
• Using your periodic tables work out which
type of bonding will be shown in these
compounds!
Br2 H2O
Cl2 Li2O
MgO
HCl N2
CaCl2
CH4
NH3 NaCl
• Extension– draw an ionic compound and a
covalent compounds

13. O C
Hint Sheet
Cl Cl

14. O C
Hint Sheet
H Cl