Lesson Plan

4. Describe the properties of metals

KS3-10-04

Intent

Learning Intention

  • Identify and describe the physical properties of metals, such as their lustre, malleability, ductility and conductivity
  • Develop skills in investigating the chemical properties of metals by carrying out experiments to measure properties such as reactivity with acids, corrosion and the formation of metal salts
  • Apply knowledge of the properties of metals to real-world situations, such as the extraction and refining of metals, the use of metals in construction and engineering, and the use of metals in everyday life

National Curriculum

  • Learn about the properties of metals in different groups of the periodic table

Working Scientifically

  • Conduct a comparative test

Learning Outcomes

  • Identify and describe the physical properties of metals, including lustre, malleability, ductility and conductivity
  • Explain the concept of chemical properties of metals and predict how metals will react in chemical reactions based on their position in the reactivity series
  • Recognise the importance of metals in industry, biology, and everyday life and understand the impact of metal use on the environment

Resources

Resources: Various metallic and non-metallic objects, electric circuit with battery and light bulb, beaker with hot water and a nail

Core Handout: A table and questions to accompany the Mission Assignment. 

Rocket words

  • malleable
  • shiny
  • sonorous
  • ductile
  • conductor

Implementation

Prior Learning 

Recap on the periodic table and the different types of elements, such as metals, nonmetals and metalloids. The students should also have a basic understanding of the atomic structure of elements, including the number of protons, neutrons and electrons.

Starter

Begin the lesson by showing an image of a metal, such as copper or iron, on the board or screen and ask students what they know about metals. Write down their responses and discuss them with the class. Introduce the topic of physical and chemical properties of metals and explain the difference between them. Ask the students to brainstorm examples of physical and chemical properties of metals.

Main Teaching

Show a sample of a metal and explain its physical properties, such as colour, lustre, malleability, ductility and conductivity. Discuss the uses of metals in industry, such as in the production of machinery, construction and electrical wiring. Introduce the concept of chemical properties and explain how they relate to the behaviour of metals in chemical reactions. Discuss the reactivity series of metals and how it affects their behaviour in reactions. Conduct a demonstration of a chemical reaction between a metal and an acid, showing the formation of a metal salt and hydrogen gas. Discuss the importance of metals in biology, such as their role in enzymes and their use in prosthetics.

Career Film: Alex Mackay is Head of Clinical Disease Knowledge at AstraZeneca.

Expert Film: Rod Rowlands explains why metals are such a useful building material.

Mission Assignment

To characterise whether a material is a metal, the students will perform a number of different tests:

  1. Place the material in the electric circuit - is the light bulb on?
  2. Take the metal sample and twist or bend it - is the material malleable?
  3. Place one end of the material in hot water for 30 seconds - is the other end warmer?
  4. Take a sharp object like a nail and scratch the surface of the material - is it shiny?

Students should reflect on why it is important to test for metallic properties and what properties all metals have in common.

Differentiated tasks (Support/Challenge)

Support:  

  • Use simplified language and visuals to explain the physical and chemical properties of metals.
  • Provide additional examples and analogies to help them understand the concepts.
  • Use hands-on activities and demonstrations to help them visualise the properties of metals.
  • Provide support during the plenary by encouraging them to share their understanding in pairs or small groups before sharing with the class.

Challenge: 

  • Provide opportunities for them to deepen their understanding of the physical and chemical properties of metals through inquiry-based activities and experiments.
  • Encourage them to explore the reactivity of metals with different acids and to investigate the factors that affect the reaction rate.
  • Differentiate the level of challenge in the activities to cater to their needs.
  • Encourage them to share their understanding with the class and to provide feedback to their peers.

Impact & Assessment Opportunities

Plenary

Recap the main points of the lesson and ask students to share one thing they have learned. Ask students to write down one physical and one chemical property of a metal they have learned. Collect the responses and discuss them with the class.

Teacher Mastery

Before you begin the experiment, talk to the students about the safety rules that need to be adhered to. Use gloves and goggles at all times during this experiment. Although gallium is non-toxic, it can leave tiny particles of liquid metal that can also turn to proper metal on the skin, which are very hard to remove.

Gallium is an element that helped to prove Mendeleev correct with regards to the missing elements in his periodic table. Mendeleev left spaces in the table where he guessed that an element was missing. When gallium was discovered, it fit right into one of the missing places in the table, just as he had predicted, 4 years earlier.

Gallium is one of the post-transition metals on the table. Post-transition metals are soft, brittle and melt quite easily. Gallium melts just above room temperature (29.76º C) and because it is also non-toxic, it has become a must safer metal to use than mercury in medical thermometers. As it wets porcelain and glass, it can be used to form a brilliant mirror finish on these materials. It is mostly used in electronics, and in the pharmaceutical industry.

This experiment shows just how easily gallium will react to being heated, even at low temperatures. The element has one of the largest liquid ranges for a metal - it's boiling point being 2372º C higher than its melting point.

The covers in the gallium experiment (paper, plastic, foil) are used to test the conductivity of the materials. Taking the control experiment (melting the gallium using just hands) as their starter point, ask them to predict how much quicker or slower it will take the gallium to melt, with the materials being used.

Did you know that gallium is safe to touch? However, we use gloves when we are going to be handling a lot of gallium because it will leave temporary stains on your hands. Also, one never really knows what they will learn about gallium (or any other element for that matter) in the future so there is no reason not to exercise some caution. It wasn't that long ago that mercury has considered as a safe metal - today we know differently.