Forming covalent bonds
Lesson details
Learning outcome
I can use dot and cross diagrams to explain how electrons are shared to form a covalent bond.
Key learning points
- In a covalent bond, two non-metal atoms share a pair of electrons (from their outer shells).
- For every one electron needed to complete the outer shell of an atom, one covalent bond will form.
- Atoms can share multiple pairs of electrons.
- Displayed formulae of covalent substances are a model, showing lines to represent shared pairs of electrons.
Keywords
Molecule - A particle consisting of a fixed number of (two or more) non-metal atoms covalently bonded together.
Covalent bond - The strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms.
Dot and cross diagram - Is used to show how chemical bonds are formed between atoms. The electrons from one atom are shown as dots and the electrons from the other atom are shown as crosses.
Empirical formula - Shows the simplest whole number ratio of atoms of each element in a compound.
Displayed formula - A 2D model of a covalent substance, showing all its atoms and bonds. Lines are used to represent shared pairs of electrons.
Common misconception
The covalent bond is the shared pair of electrons; both electrons must come from different atoms. The central atom is responsible for the formation of covalent bonds as they want a full outer shell.
All chemical bonds are an electrostatic force of attraction between positive and negative charges. The sharing of electrons is the process by which covalent bonds are formed. Avoid using anthropomorphic analogies to explain how covalent bonds form.
Teacher tip
Use molecular modelling kits to demonstrate the number of covalent bonds each atom can from and to point out which atom is sharing its outer shell electron. Encourage students to think about the chemical elements as chemicals and build on previous learning about why chemical reactions occur.
Equipment
molecular modelling kits
Licence
except where otherwise stated. See Oak's terms & conditions (Collection 2).Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.Why do atoms form chemical bonds?
Q2.Which type of bond forms between atoms that have transferred electrons from one atom to another?
Q3.What type of elements typically form ionic bonds?
Q4.How many outer-shell electrons does an oxygen atom have?
Q5.A is a particle consisting of two or more non-metal atoms bonded together. It can be made up of the same or different elements.
Q6.Arrange the following molecules by the number of covalent bonds each has, from least to most:
Assessment exit quiz
6 Questions
Q1.What is a covalent bond?
Q2.How many covalent bonds will an atom form if it needs three electrons to complete its outer shell?
Q3.What does a displayed formula of a covalent substance show?
Q4.What is the purpose of a dot and cross diagram?
Q5.A is a particle consisting of a fixed number of non-metal atoms covalently bonded together.
Q6.Atoms can share multiple pairs of electrons to achieve full outer shells, leading to double or covalent bonds.
To help you plan your 10 chemistry lesson on: Forming covalent bonds, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 10 chemistry lesson on: Forming covalent bonds, download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
We use learning cycles to break down learning into key concepts or ideas linked to the learning outcome. Each learning cycle features explanations with checks for understanding and practice tasks with feedback. All of this is found in our slide decks, ready for you to download and edit. The practice tasks are also available as printable worksheets and some lessons have additional materials with extra material you might need for teaching the lesson.
The assessment exit quiz will test your pupils' understanding of the key learning points.
Our video is a tool for planning, showing how other teachers might teach the lesson, offering helpful tips, modelled explanations and inspiration for your own delivery in the classroom. Plus, you can set it as homework or revision for pupils and keep their learning on track by sharing an online pupil version of this lesson.
Explore more key stage 4 chemistry lessons from the Structure and bonding unit, dive into the full secondary chemistry curriculum, or learn more about lesson planning.