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Lesson Plans Library 6-8 > Physical Science
Alkali Metals
Alkali Metals
Grade level: 6-8 Subject: Physical Science Duration: Two class periods
 


lesson plan support
Objectives
Students will
  • Identify basic properties of metals and the different types of metals.
  • Find alkali metals on the periodic table and review their key properties.
  • Discuss the use of alkali metals and other elements in the creation of fireworks.
  • Create a mural of fireworks, highlighting at least five metals used to make the different colors and effects.
Materials
  • Alkali Metals video
  • Periodic table
  • Large rolls of paper and markers to create murals
  • Index cards (five for each group of students)
  • Print and online resources about how fireworks are created
  • Computer with Internet access
Procedures
  1. Have students name some common metals and write their names and atomic symbols on the board. For example, iron (Fe), copper (Cu), Silver (Ag), platinum (Pt), gold (Au). Ask students to predict the common properties of metals and make a list of their answers. Most metals are:
    • hard
    • shiny
    • solid at normal temperature (except Mercury)
    • good conductors of heat and electricity
    • malleable (can be flattened into sheets)
    • ductile (can be stretched into long wires)
  2. Next, show students where metals are found on the periodic table. Point out that there are different types of metals, each with unique properties: alkali metals, alkaline-earth metals, transition metals, and other metals. Metals can be identified on the periodic table by the columns, or groups, in which they're found. At this point, you may want to review with students how the periodic table is organized:
    • The elements are arranged in order of atomic number, or number of protons.
    • Elements in the same row, or period, are made of atoms with the same number of electron shells.
    • Elements in the same column, or group, are made of atoms with the same number of electrons in their outer shell. They also share similar properties.
  3. Find the Alakali Metals (group 1) on the periodic table. How many electrons do these elements have in their outermost shell? (one) What effect does this have on these elements? (They are inclined to lose their outer electron and therefore highly reactive.) Using what they learned in the video, ask students to list the key properties of alkali metals:
    • Soft
    • Tarnish readily
    • Low melting points
    • Low densities
    • Violently reactive
  4. Explain that the alkali metal sodium was used to create the first explosive. Two Chinese alchemists accidentally discovered the explosive by mixing charcoal, sulfur, and saltpeter ? a sodium compound. Before long, explosives were used to create the first fireworks. While today's fireworks are far more complex, they still rely on alkali metals and other elements to create different colors and effects.
  5. Tell students that they are going to work in small groups to research the different elements used to create fireworks. Then they will create a mural of a fireworks display highlighting at least five metals used to make the different colors and effects. At least one metal should be an alkali metal. Give each group a large sheet of paper, markers, and five large index cards. On each index card, they should provide information for one metal used in their fireworks display. The card should be placed on their mural next to the appropriate firework and include the following information:
    • Element Name and Atomic Symbol: [Copper (Cu)]
    • Type of metal: [Transition Metal]
    • Use or Effect: [Creates blue fireworks]
  6. Provide students with print and online resources about fireworks, such as the following websites. They may want to begin with the first two websites to learn about different fireworks shapes and effects. The other two websites provide information about different elements used to create fireworks.
  7. Once students have completed their murals, have each group present their fireworks display to the class

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Evaluation
Use the following three-point rubric to evaluate students' work during this lesson.
  • Three points: Students were active in class discussions; showed a strong understanding of metals, alkali metals, and the periodic table; developed a creative, attractive, and varied mural highlighting at least five metals; index cards identifying metals were accurate and complete.
  • Two points: Students participated in class discussions; showed a satisfactory understanding of metals, alkali metals, and the periodic table; developed an acceptable mural highlighting five metals; index cards identifying metals were mostly accurate and complete.
  • One point: Students did not participate in class discussions; showed a weak understanding of metals, alkali metals, and the periodic table; developed an complete or sloppy mural highlighting less than metals; index cards did not accurately identify metals or were incomplete.

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Vocabulary
alkali metal
Definition: A highly reactive metallic element belonging to group 1 of the periodic table, including: lithium, sodium, potassium, rubidium, cesium, and francium
Context: The alkali metals are as soft as cold butter and much less dense than most other metals.

element
Definition: A substance that is composed of one type of atom; an element cannot be chemically separated
Context: Sodium is the sixth most abundant element on Earth.

reactive
Definition: Taking part in a chemical reaction, as in an element
Context: Alkali metals are so reactive that they interact with most other elements they come into contact with.

valence electrons
Definition: The electrons in an atoms outermost electron shell that dictate how elements interact
Context: The single valence electron in the alkali metals makes them very unstable and they easily lose this electron to other elements.

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Academic Standards

Mid-continent Research for Education and Learning (McREL)
McREL's Content Knowledge: A Compendium of Standards and Benchmarks for K-12 Education addresses 14 content areas. To view the standards and benchmarks, visithttp://www.mcrel.org/compendium/browse.asp.
This lesson plan addresses the following national standards:

  • Science-Physical Sciences: Understands the structure and properties of matte

National Academy of Sciences
The National Academy of Sciences provides guidelines for teaching science in grades K-12 to promote scientific literacy. To view the standards, visit this Web site:
http://books.nap.edu/html/nses/html/overview.html#content.
This lesson plan addresses the following national standards:

  • Physical Science
  • Science and Technology

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