Chemistry - 4CH1 PearsonEdexcel

Group 7 (halogens) – Chlorine, Bromine And Iodine

Overview

Open a bottle of bleach and the sharp smell reaching your nose is chlorine, one of the halogens. These five reactive non-metals sit in Group 7 of the periodic table, and despite ranging from a pale yellow gas to a dark solid, they form a tight chemical family with predictable patterns.

In this lesson you will compare the physical properties and colours of chlorine, bromine and iodine, investigate displacement reactions that prove their reactivity order, and explain why reactivity decreases down the group using electronic configurations.

Objectives

  1. know the colours, physical states (at room temperature) and trends in physical properties of these elements
  2. use knowledge of trends in Group 7 to predict the properties of other halogens
  3. understand how displacement reactions involving halogens and halides provide evidence for the trend in reactivity in Group 7
  4. explain the trend in reactivity in Group 7 in terms of electronic configurations

Lesson Note

Chlorine sterilises drinking water. Iodine is a wound antiseptic. Bromine compounds once filled fire extinguishers. The halogens are among the most reactive non-metals on the periodic table, and the way their reactivity changes from fluorine to astatine mirrors the Group 1 metals in reverse: here, the lightest element is the most reactive, not the least. Understanding why requires a look at how easily these atoms can grab an extra electron.

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Lesson Evaluation

Congratulations on completing the lesson on Group 7 (halogens) – Chlorine, Bromine And Iodine. 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. Which halogen is a liquid at room temperature? A) Fluorine B) Chlorine C) Bromine D) Iodine Answer: C
  2. What happens when bromine water is added to potassium chloride solution? A) The solution turns brown B) The solution turns orange C) Chlorine gas is released D) No reaction occurs Answer: D
  3. The reactivity of the halogens decreases down the group because: A) The atoms get smaller B) The outer shell is further from the nucleus, making it harder to gain an electron C) They lose electrons more easily D) They have fewer protons Answer: B
  4. Which of the following correctly describes the trend in boiling point down Group 7? A) Decreases B) Stays the same C) Increases D) Increases then decreases Answer: C
  5. Chlorine can displace bromine from potassium bromide solution because: A) Chlorine is less reactive than bromine B) Chlorine is more reactive than bromine C) Bromine is a gas D) Potassium is more reactive than chlorine 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
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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

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