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Lesson Plans Library 9-12 >Physical Science
Periodic Table of the Elements Transition Metals II
Periodic Table of the Elements Transition Metals II
Grade level: 9-12 Subject: Physical Science Duration: 1 class period
 



lesson plan support
Objectives
Students will
  • Explore transition metals.
  • Explain why transition metals are used in coins.
  • Describe why oxides such as rust and tarnish form on metals.
Materials
  • Periodic Table of the Elements: Transition Metals IIprogram
  • Measuring cup
  • 1/4 cup vinegar
  • Pinch of salt
  • Clean glass jar
  • 10 dirty pennies (from before 1982)
  • Paper towels
  • Two new, untarnished iron nails
  • Small bowl of water
Procedures
  1. After watching the video, ask students to name examples of transition metals. (iron, nickel, titanium, copper, silver, gold, chromium, iron, zinc) Point out the transition metals on a periodic table. Ask students to identify some properties of most transition metals. (hard, dense, shiny, high melting and boiling points, good conductors of heat and electricity, malleable, and ductile)

  2. Tell the class that they?re going to conduct an experiment with the transition metal copper in the form of old pennies. Explain that today pennies contain just a coating with 2.5 percent copper, but pennies made before 1982 contain 95 percent copper. Divide students into teams of three or four and give each team the materials listed above.

  3. Have each team pour 1/4 cup of vinegar into a glass jar. Add a pinch of salt and stir. Put 10 dirty pennies and one of the nails into the jar. Let sit for 10 minutes.

  4. While waiting, explain that copper isn?t the only transition metal in coins. In fact, all metals tin U.S. coins are transition metals. Challenge students to name the three transition metals that are found in all current U.S. coins. (copper, zinc, nickel) What additional metal is found in the new golden dollar? (manganese) Which three coins have the exact same composition, including the percentage of each metal? (dime, quarter, half dollar) You may want to share and discuss the chart below about the composition of today?s U.S. coins.

    Penny Nickel Dime Quarter Half Dollar Dollar (Susan B. Anthony) Golden Dollar (Sacagawea)

    2.5% Cu
    Balance Zn

    25% Ni
    Balance Cu

    8.33% Ni
    Balance Cu

    8.33% Ni
    Balance Cu

    8.33% Ni
    Balance Cu

    12.5% Ni
    Balance Cu

    88.5% Cu
    6% Zn
    3.5% Mn
    2% Ni


  5. Talk about why transition metals are ideal for coins. (They are malleable; they can be shaped or imprinted without breaking. Other materials might be crushed or shattered under the pressure. Also, they are strong enough to resist the wear of everyday use.)

  6. After 10 minutes, have teams remove five pennies and place them on a paper towel. Then have them remove the other five pennies, rinse them in the bowl of water, dry them, and place them on another paper towel. Explain that the nail stays in the vinegar mixture for 10 more minutes.
  7. Ask students to describe the pennies. (They look bright and shiny.)To understand why this happens, talk about what causes pennies to tarnish.(A chemical reaction takes place between the copper and oxygen. The copper atoms and oxygen atoms form molecules called copper oxide. An oxide is a compound that forms when oxygen reacts with a metal.The copper oxide is the tarnish on the penny.)Other examples of oxide are the rust on an iron gate or the tarnish on a silver cup; these oxides occur because oxygen reacts with iron and silver just as it does with copper.
  8. Using what they?ve just learned, students should describe what happened to the pennies in the vinegar. (The salt and vinegar wore away the oxide layer, or tarnish, on the pennies.)

  9. If time permits, talk about the harmful affects of oxidation. For example, over time rust or tarnish can cause metals to corrode. What are some ways that people prevent oxidation?

  10. After the 10 additional minutes, remove the iron nail and place it on a paper towel. Compare it to the nail left out of the vinegar solution. What happened to the nail? (It should have a sticky brown coating.) What is the brown substance? (copper) Where did the copper come from? (copper oxide from the pennies) Explain that when the copper ions from the pennies were released into the vinegar, they reacted with the iron in the nail to produce the copper coating.
  11. Have students hypothesize what the nail might have looked like if they had used pennies made after 1982.

  12. Now observe and compare the two sets of pennies. Ask students to turn the pennies over and observe both sides. How do the two sets look different? (Those rinsed and dried should look bright and shiny. A faint, blue-green coating will be visible on the others.) The blue-green coating is a compound called malachite that formed from a reaction between the copper, salt, and oxygen. The vinegar solution on the pennies promotes this reaction. (NOTE: Some malachite will begin to appear by the end of the class period, and it will be much more noticeable the following day. If possible, leave the pennies out and observe them again.)
  13. To conclude the lesson, have students write a short paragraph to describe an example of where to find an oxide, including an explanation of why it formed.

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Evaluation
Use the following three-point rubric to evaluate students' work during this lesson.
  • Three points: Students shared several examples and properties of transition metals; identified the transition metals used in coins and explained why these metals are used; wrote a clear and accurate explanation of why oxides such as rust and tarnish form on metals.
  • Two points: Students shared a few examples and properties of transition metals; identified at least one transition metal used in coins and explained why these metals are used; wrote a satisfactory explanation of why oxides such as rust and tarnish form on metals.
  • One point: Students shared few or no examples and properties of transition metals; could not identify the transition metals used in coins or explain why these metals are used; wrote an unclear or inaccurate explanation of why oxides such as rust and tarnish form on metals.

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Vocabulary
alloy
Definition:A solid substance made by mixing a metal with another substance, usually another metal
Context:The U.S. Mintís a new dollar coin is made with an alloy of copper, nickel, zinc, and manganese.

conductor
Definition:A material through which electric current flows easily
Context:Copper is an excellent conductor of electricity and heat, making it useful for electrical equipment and cookware.

ductile
Definition:Able to be drawn into a wire
Context:Like most transition metals, gold is ductile and can be flattened.

malleable
Definition:Able to be hammered or pressed without breaking
Context:The malleable nature of the transition metals makes them ideal for coins.

metal
Definition:An element that is a good conductor of heat and electricity and is usually shiny and hard at normal temperature
Context:Silver is a popular metal for use as jewelry, coinage, and household objects.

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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,click here.
This lesson plan addresses the following national standards:
  • Science?Physical Sciences: Understands the structure and properties of matter
  • Technology: Understands the nature of technological design

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,click hereto visit the Web site.
This lesson plan addresses the following national standards:

  • Physical Science
  • Science and Technology

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