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ElementsElements

  • Subject: Physical Science
  • |
  • Grade(s): 6-8
  • |
  • Duration: One class periods

Lesson Plan Sections

Objectives


Students will understand the following:
1. When Mendeleyev arranged the 60 elements known at that time into the periodic table, there were gaps. Mendeleyev was able to predict the properties of the "missing," yet-to-be-discovered elements by analyzing the nearest known elements in the table.
2. Since Mendeleyev devised the periodic table, other elements have been discovered by scientists.
3. Many of the elements have been put to practical uses or affected society in important ways since their discoveries.

Materials


For this lesson, you will need:
• Periodic table of the elements
• Research materials on the elements and on important scientists
• Computer with Internet access

Procedures


1. Review with students what they have learned about the periodic table of the elements. Ask such questions as Who devised the periodic table? How did Mendeleyev know that there were gaps in the table? How was he able to predict the properties of the ?missing,' yet-to-be-discovered elements?
2. Ask students if they know how the gaps have been filled. They should recognize that scientists have discovered "new"elements since the time of Mendeleyev.
3. Assign each member of your class one of the elements in the periodic table, asking each student to research the element he or she has been assigned in order to answer the following questions: What was the date of the element's discovery? Which scientist or scientists discovered the element? Where was the element discovered? Under what circumstances was it discovered?
4. Have students write paragraphs answering the above questions. You can also encourage each student to write an additional paragraph about any uses or products that have developed from the discovery of his or her element or ways in which the element has affected society. (For example, the isolation of iron led to the manufacturing of weapons and tools during the Iron Age.)
5. As students present their findings to the class, have students work together to create an annotated time line that shows the date of each element's discovery.

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Adaptations


Adaptations for Older Students:
Hold a discussion with the class about factors that will inhibit the discovery or creation of new elements in the future.

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Discussion Questions


1. Air was once thought of as a pure element—it didn't seem to our human senses to be "made up" of anything, so the idea made sense. With advances in laboratory equipment and techniques, however, Joseph Priestley was able to prove that air is actually a combination of elements. Discuss how scientific discoveries can change our sometimes-simple ways of perceiving the world.
2. Explain how the ancient Greeks reasoned that wood was made up of different amounts of the four basic elements (as they saw them): earth, air, fire, and water.
3. Discuss what characteristics make an inorganic element valuable to human society. Is it the element's rarity, usefulness, monetary worth, or another measure of value? Explain why different inorganic elements were more prized at different points in human history. Which inorganic elements do you think are the most valuable today? Why?
4. Discuss the idea of alchemists trying to transmute lead into gold. Does it seem foolish? If we could develop the technology to build atoms from their subatomic particles, how would this change our world? How would we measure wealth? What would make one country more powerful than any other?
5. The element hydrogen is a highly flammable gas, but when two atoms of hydrogen are combined with one atom of oxygen, the result is water, which certainly doesn't burn. Explain how such different compounds can exist and yet still contain the element hydrogen. How can you determine how certain chemical compounds will react?
6. Debate whether an element that is made by scientists in a linear accelerator by the collision of high-speed particles and that exists for only a fraction of a second should be considered an element.

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Evaluation


You can evaluate your students on their written work using the following three-point rubric:
  • Three points: all questions answered accurately; paragraph(s) well organized and error-free
  • Two points: most questions answered accurately; paragraph(s) adequately organized with few errors
  • One point: answers to several questions omitted; paragraph(s) poorly organized with numerous errors
You can ask your students to contribute to the assessment rubric by reviewing the criteria for a well-organized paragraph.

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Extensions


The Dramatic Element
Divide your students into research teams, and assign each team either the alkali, metal, or noble gas groups of the elements that make up the periodic table. Ask the teams to investigate the basic properties of the elements in the group they have been assigned. The teams should also include the element hydrogen in their study: Point out that hydrogen does not belong to any group but stands alone in the periodic table. When their research is complete, ask each team to express its new knowledge of the elemental group they have studied by writing and performing skits in which they personify each of the elements in their assigned group. The skit's dramatic action should be based on the interaction—or, in the case of the noble gasses, noninteraction—with the other elements of the group. Since hydrogen reacts with many other elements, they should also include a hydrogen "character" in their skits. One interesting extension to this activity is to have students perform short ad-libs between element characters from other groups. This will give students the chance to demonstrate their understanding of the ways in which different elements interact.

What If . . . ?
Ask your students to imagine that one day, out of nowhere, one of the elements in the periodic table suddenly starts to disappear from the face of Earth. Depending on the element, the results could be cataclysmic. Assign each student one of the elements from the table (or allow each to choose his or her own element); then ask them to write a fictionalized "firsthand" account of the day their element disappeared. (An example: the day Earth lost its iron—buildings crumble, bridges collapse, blood gradually becomes anemic, and so on.) In order to accomplish this end, students will need to research some of the basic uses of the elements they are working with. Where do they appear in nature, if at all? How are they used by scientists, engineers, artists, doctors, and so on? Where are their presences crucial? How would life be different without them? Would life even be able to survive? When students' stories are complete, ask for volunteers to stage dramatic readings of their work. You may also want to collect students' writing into a "periodic table of disasters" to share with another class or publish on your school's Web site.

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Suggested Readings


A Guide to the Elements
Albert Stwertka. Oxford University Press, 1996.
This beautiful book is devoted to making the elements easily understandable. Stwertka begins with an introductory session on the basic concepts of chemistry and the history of the periodic table, then discusses each element in separate articles. The book also includes photographs and examples of each element's practical applications.

Elements
Brian Knapp. Grolier Educational, 1996.
This 15-volume set provides an accessible approach to the elements. Each element is highlighted in its own volume. The volumes contain descriptions of each element's characteristics, behavior, and occurrence, as well as step-by-step demonstrations that link each element to its real-world applications.

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Links


How Did the Elemental Composition of the Universe Evolve?
Where did all the variety of atoms in the periodic chart come from, and where is it all going? This web site introduces us to the evolution of matter from its least complex to most complex form.

Cool Chemistry Laboratory
Aloha! Here's your chance to take a trip to the University of Hawaii and surf through the best multimedia tutorial that introduces basic concepts in chemistry. A Shock Wave plug-in is required and may be downloaded from this web site.

Periodic Nexus
At the Table Primer get primed up about how the whole periodic table works. Interesting chemical factoids jump out at you as you navigate this site.

Supernova Chemistry
Students will observe visible spectra of known elements here on Earth and identify unknown elements or combination of elements by visible spectra emitted from distant stars.

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Vocabulary


Click on any of the vocabulary words below to hear them pronounced and used in a sentence.
speaker    alchemy
Definition: A medieval chemical science and speculative philosophy aiming to achieve the transmutation of the base metals into gold, the discovery of a universal cure for disease, and the discovery of a means of indefinitely prolonging life.
Context: Scholars during the Middle Ages practiced alchemy, mixing different substances in the hopes of turning lead into gold.
speaker    compound
Definition: A distinct substance formed by chemical union of two or more ingredients in definite proportion by weight.
Context: Water is a widely known chemical compound.
speaker    empirical
Definition: Originating in or based on observation or experience.
Context: Rather than guessing which element interacts with carbon, scientists make their decision using empirical evidence.
speaker    inert
Definition: Deficient in active properties; lacking a usual or anticipated chemical or biological action.
Context: Elements that don't readily interact with other elements are known to be inert.
speaker    organic
Definition: Of, relating to, or containing carbon compounds; relating to, being, or dealt with by a branch of chemistry concerned with the carbon compounds of living beings and most other carbon compounds.
Context: Carbon is the most important element in organic chemistry.

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Standards


This lesson plan may be used to address the academic standards listed below. These standards are drawn from Content Knowledge: A Compendium of Standards and Benchmarks for K-12 Education: 2nd Edition and have been provided courtesy of theMid-continent Research for Education and Learningin Aurora, Colorado.
 
Grade level: 6-8, 9-12
Subject area: physical science
Standard:
Understands basic concepts about the structure and properties of matter.
Benchmarks:
6-8: Knows that matter is made up of tiny particles called atoms, and different arrangements of atoms into groups compose all substances.

6-8: Knows that atoms often combine to form a molecule (or crystal), the smallest particle of a substance that retains its properties.

6-8: Knows that substances that contain only one kind of atom are pure elements, and more than 100 different elements exist; elements do not break down by normal laboratory reactions.

6-8: Knows that many elements can be grouped according to similar properties.

6-8: Knows that substances react chemically in characteristic ways with other substances to form new substances with different characteristic properties.

9-12: Understands how elements are arranged in the periodic table and how this arrangement shows repeating patterns among elements with similar properties.

9-12: Knows how the electron configuration of atoms governs the chemical properties of an element as atoms interact with one another by transferring or sharing electrons that are furthest from the nucleus.

9-12: Knows that atoms may be bonded together into molecules or crystalline solids, and compounds are formed from chemical bonds between two or more different kinds of atoms.

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Credit


Audrey Carangelo, freelance curriculum developer.

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