Science Double Award - 4SD0 PearsonEdexcel

Covalent Bonding

Overview

Most of the substances you encounter every day, from the water you drink to the plastic in your phone case, are held together by covalent bonds. Unlike ionic bonding, where electrons are transferred, covalent bonding involves atoms sharing pairs of electrons so that each atom achieves a stable outer shell.

In this lesson you will learn how covalent bonds form, practise drawing dot-and-cross diagrams for key molecules, and explore why simple molecular substances have low melting points while giant covalent structures like diamond and graphite are among the hardest materials on Earth. These concepts appear regularly on both Paper 1 and Paper 2.

Objectives

  1. Know that a covalent bond is formed between atoms by the sharing of a pair of electrons
  2. Understand covalent bonds in terms of electrostatic attractions
  3. Understand how to use dot-and-cross diagrams to represent covalent bonds in diatomic, inorganic and organic molecules
  4. Explain why substances with simple molecular structures are gases or liquids, or solids with low melting and boiling points
  5. Explain why the melting and boiling points of substances with simple molecular structures increase with increasing relative molecular mass
  6. Explain why substances with giant covalent structures are solids with high melting and boiling points
  7. Explain how the structures of diamond, graphite and C60 fullerene influence their physical properties
  8. Know that covalent compounds do not usually conduct electricity

Lesson Note

Salt dissolves in water and conducts electricity. Wax melts at low temperatures and does not conduct at all. The difference comes down to bonding. In ionic compounds, electrons are transferred between metals and non-metals. In covalent compounds, non-metal atoms share pairs of electrons, forming a bond that holds the atoms together without creating ions.

Available on the Green Bridge App

Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.

Full lesson notes with diagrams
AI-powered learning assistant
Study offline, anytime, anywhere
Available on Android, Windows, macOS, and Linux

Lesson Evaluation

Congratulations on completing the lesson on Covalent Bonding. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.

You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.

Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.

  1. What is a covalent bond? A) A bond formed by transferring electrons from a metal to a non-metal B) A bond formed by sharing a pair of electrons between two non-metal atoms C) A bond formed by the attraction between positive and negative ions D) A bond formed by delocalised electrons in a metal Answer: B
  2. How many covalent bonds does a carbon atom typically form? A) 1 B) 2 C) 3 D) 4 Answer: D
  3. Which substance has a giant covalent structure? A) Water B) Carbon dioxide C) Diamond D) Hydrogen chloride Answer: C
  4. Why do simple molecular substances have low boiling points? A) Their covalent bonds are weak B) Their intermolecular forces are weak C) They contain ions that separate easily D) They have delocalised electrons Answer: B
  5. Which allotrope of carbon can conduct electricity? A) Diamond B) Graphite C) Both diamond and graphite D) Neither diamond nor graphite Answer: B

Available on the Green Bridge App

Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.

Full lesson notes with diagrams
AI-powered learning assistant
Study offline, anytime, anywhere
Available on Android, Windows, macOS, and Linux

Available on the Green Bridge App

Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.

Full lesson notes with diagrams
AI-powered learning assistant
Study offline, anytime, anywhere
Available on Android, Windows, macOS, and Linux

Practice Mock Questions

Want to practice mock questions on Covalent Bonding? Download the Green Bridge CBT app to access mock questions and full practice assessments for this topic.

Download The App On Google Playstore

Everything you need to excel in your exams

Green Bridge CBT Mobile App
Personalized AI Learning Chat Assistant
200,000+ Past Papers Across IGCSE, JAMB, WAEC & NECO
Over 3000 Lesson Notes
Offline Support - Learn Anytime, Anywhere
Green Bridge Timetable
Literature Summaries & Potential Questions
Track Your Performance & Progress
In-depth Explanations for Comprehensive Learning