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
- Know that a covalent bond is formed between atoms by the sharing of a pair of electrons
- Understand covalent bonds in terms of electrostatic attractions
- Understand how to use dot-and-cross diagrams to represent covalent bonds in diatomic, inorganic and organic molecules
- Explain why substances with simple molecular structures are gases or liquids, or solids with low melting and boiling points
- Explain why the melting and boiling points of substances with simple molecular structures increase with increasing relative molecular mass
- Explain why substances with giant covalent structures are solids with high melting and boiling points
- Explain how the structures of diamond, graphite and C60 fullerene influence their physical properties
- Know that covalent compounds do not usually conduct electricity
Mind map
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Flashcards
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Lesson Note
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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.
- 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
- How many covalent bonds does a carbon atom typically form? A) 1 B) 2 C) 3 D) 4 Answer: D
- Which substance has a giant covalent structure? A) Water B) Carbon dioxide C) Diamond D) Hydrogen chloride Answer: C
- 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
- Which allotrope of carbon can conduct electricity? A) Diamond B) Graphite C) Both diamond and graphite D) Neither diamond nor graphite Answer: B
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Practice Mock Questions
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