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Year 10 - Science

Forming covalent bonds

Structure and bonding

Unit Summary

This unit explores changes of state, particle kinetics, and energy transfers in relation to chemical bonding, including ionic, covalent, and metallic bonds. It examines carbon's unique bonding properties, leading to organic compounds and materials like diamond, graphite, fullerenes, and graphene.

Lesson Summary

You will learn to use dot and cross diagrams to explain how electrons are shared to form a covalent bond.

Key Notes

  • 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.

Vocabulary To Learn

  • 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 Mistakes To Avoid

  • 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.

3 Quick Questions (With Answers)

1. Explain the scientific idea in this lesson using two key 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.

2. Define this scientific word and use it in context. 'molecule'

A particle consisting of a fixed number of (two or more) non-metal atoms covalently bonded together. Include the word in a full scientific explanation, not as a single label.

3. Correct this common scientific misunderstanding.

Mistake: 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. Correction: 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.

More Lessons In This Unit

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