Simple Molecules And Covalent Bonds
Overview
The oxygen you breathe, the water you drink and the methane that heats your food are all held together not by transferring electrons but by sharing them. This sharing creates the covalent bond, the glue of most non-metal compounds and the basis of all living matter.
In this lesson you will learn how a covalent bond forms when atoms share a pair of electrons, how to show this with simple diagrams, and how shared pairs build up familiar molecules such as hydrogen, water, methane and carbon dioxide.
Objectives
- State that a covalent bond is formed when a pair of electrons is shared between two atoms leading to noble gas electronic configurations.
- Describe the formation of covalent bonds in simple molecules, including H₂, Cl₂, H₂O, CH₄, NH₃ and HCl. Use dot-and-cross diagrams to show the electronic configurations in these and similar molecules.
- Describe in terms of structure and bonding the properties of simple molecular compounds: (a) low melting points and boiling points (b) poor electrical conductivity.
- [Supplement] Describe the formation of covalent bonds in simple molecules, including CH OH, C H , O , 3 2 4 2 CO and N . Use dot-and-cross diagrams to 2 2 show the electronic configurations in these and similar molecules.
- [Supplement] Explain in terms of structure and bonding the properties of simple molecular compounds: (a) low melting points and boiling points in terms of weak intermolecular forces (specific types of intermolecular forces are not required) (b) poor electrical conductivity.
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Lesson Evaluation
Congratulations on completing the lesson on Simple Molecules And Covalent Bonds. 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.
- A covalent bond is formed when atoms: A. Transfer electrons B. Share a pair of electrons C. Lose protons D. Gain neutrons Answer: B
- Covalent bonds usually form between: A. Two metals B. A metal and a non-metal C. Two non-metals D. Two ions Answer: C
- How many covalent bonds does carbon form in methane, CH4? A. 1 B. 2 C. 3 D. 4 Answer: D
- Simple molecular substances have low melting points because: A. The covalent bonds are weak B. The forces between molecules are weak C. They contain ions D. They have free electrons Answer: B
- Carbon dioxide, CO2, contains: A. Two single bonds B. Two double bonds C. One single bond D. Ionic bonds Answer: B
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