It s in the Cards. Introduction to the Periodic Table

Transcription

1 Middle Grades Science It s in the Cards Introduction to the Periodic Table MATERIALS AND RESOURCES EACH GROUP cards, colored pattern ABOUT THIS LESSON In this lesson, students will be given a set of cards that contain certain patterns. Students will attempt to put the cards into some logical order. They will be asked to explain their reasoning to their classmates and to construct four rules that govern the arrangement of the cards. Working in small groups, the students are then asked to predict the two missing cards. OBJECTIVES T E A C H E R P A G E S Students will: Arrange the cards in an order that is logical and systematic Formulate four rules that govern the arrangement of the cards Predict the missing two cards LEVEL Middle Grades: Chemistry i

2 Middle Grades Science It s in the Cards NEXT GENERATION SCIENCE STANDARDS COMMON CORE STATE STANDARDS!! (LITERACY) RST Cite specific textual evidence to support analysis of science and technical texts. DEVELOPING AND USING MODELS ENGAGING IN ARGUMENT FROM EVIDENCE (LITERACY) RST Follow precisely a multistep procedure when carrying out experiments, taking measurements, or performing technical tasks. PATTERNS (LITERACY) WHST Write arguments focused on discipline-specific content. ASSESSMENTS PS1: MATTER CONNECTIONS TO AP* AP CHEMISTRY 1 *Advanced Placement and AP are registered trademarks of the College Entrance Examination Board. The College Board was not involved in the production of this product. LESSON CONSUMABLES Item 1 Blue Periodic Cards Item 2 Green Periodic Cards Item 3 Red Periodic Cards Item 4 Yellow Periodic Cards The following types of formative assessments are embedded in this lesson: Visual assessment of student generated arrangements Verbal communication of four rules Prediction of two missing cards The following assessments are located on our website: Middle Grades Chemistry: Atomic Properties and Periodic Trends Assessment th Grade Posttest, Free Response Question IPC Posttest, Free Response Question 1 ACKNOWLEDGEMENTS itunes is a registered trademark used with permission from Apple, Inc. Copyright 2013 Apple Inc. All rights reserved. T E A C H E R P A G E S ii

3 Middle Grades Science It s in the Cards TEACHING SUGGESTIONS Each student group will receive an envelope containing 18 cards. Only six cards are removed initially, and the group attempts to arrange the cards in a logical order based upon observed patterns. It is very important that the students do not look at the other 12 cards. During this time, ask student groups to explain to you why they arranged the six cards in the particular order that they chose. Ask them how the cards are similar and how they are different. Emphasize that scientific knowledge depends upon evidence. In addition, scientific knowledge is continually being revised based upon new evidence. Next, tell each student group they may remove six more cards from the envelope. Remind the students that this activity also illustrates the collaborative nature of science. Students must search for clues, look for patterns and connections, and be willing to rearrange the order of their cards. During this time, ask student groups to explain to you why they arranged the 12 cards in the particular order that they chose. As arranged, do the cards make sense whether reading across the rows or down the columns? Inform the students that they may want to leave room for cards they think are missing. Allow each group to work until it appears they have exhausted their individual lines of thought and have recorded their tentative rules. Announce to each student group they may remove the remaining cards from their envelope. Remind students that data is not always consistent and all of the evidence may not be available. For reluctant learners, you may need to share with them that the pattern is a 4 5 or 5 4. It is important to point out to students that when Dmitri Mendeleev constructed his periodic table in 1869, he left room for elements that were not yet discovered. Mendeleev recognized that just as in the card game Solitaire where some of the cards are hidden, so too his periodic table was incomplete as there were elements that had yet to be discovered. Mendeleev predicted that there should be an element in the periodic table between silicon and tin, which he called eka-silicon. In 1886 germanium was discovered, which turned out to be eka-silicon and to have the properties predicted by Mendeleev s periodic table. 1 Share with the students that there are two cards missing and they are to predict what those cards are based upon the four rules they have formulated. Mendeleev maintained that the chemical properties of the elements were determined by atomic weight. This was perfectly reasonable against the backdrop of scientific knowledge in Today we know that elements are different from one another because their atoms have different numbers of protons, not because of their atomic weights. 2 Thus, the chemical elements are arranged in order of increasing atomic number (number of protons) as we move from left to right across the periodic table. Tell your students that in this simulation, we have some modern technology that has now allowed us to make better measurements. Place your finger on the fingernail sketch at the bottom of the card such that the numbers that are now exposed are the atomic numbers for the elements in the periodic table. They may now determine what elements the cards represent if you want to extend the lesson. T E A C H E R P A G E S 1 Lederman, Leon M., and Dick Teresi. The God Particle: If the Universe Is the Answer, What Is the Question? New York: Houghton Mifflin, 1993, p. 115 (information of Mendeleev s chemical solitaire). 2 Lederman and Teresi, p iii

4 Middle Grades Science It s in the Cards TEACHING SUGGESTIONS (CONTINUED) Finally, point out to students that they have not done an experiment but have simulated the chemical solitaire that led Mendeleev to construct the periodic table. Allow students to answer the Conclusion Questions either individually or collaboratively. Engage the class in sharing and discussing their answers, guiding their understanding toward the big idea that evidence provides power to make quality predictions. Students need a thorough understanding of atomic structure and periodic trends to be successful on the AP Chemistry examination and, indeed, to be successful in the field of chemistry in general. This exercise provides an introduction to the periodic table and the idea that there are trends in the rows and columns that make up the periodic table. When explaining the reasons behind the trends, it is helpful to start with atomic radii or size of the atoms. As one moves down a family, additional energy levels are added and the atoms get larger. As more levels are added, there are more electrons between the nucleus and the outer energy level. These electrons shield the nucleus from holding tightly to the outer electrons. As one moves across a period from left to right, the electrons are in the same energy level but each successive atom has one more proton in the nucleus. The additional proton increases the nuclear charge, or it increases the Z eff (Z effective) without increasing any inner shielding. This causes the electrons to be drawn closer to the nucleus. Size is the easiest trend for students to understand and, once students grasp this concept, other concepts such as ionization energy, electron affinity, and electronegativity are easily understood. This activity can be followed up with the activity, Why Do They Call It a Periodic Table? T E A C H E R P A G E S iv

5 Middle Grades Science It's in the Cards DATA AND OBSERVATIONS 6 CARDS: Observations will vary. 18 CARDS: Observations will vary. 12 CARDS: Observations will vary. A N S W E R K E Y Figure A. Periodic cards key v

6 Middle Grades Science It's in the Cards ANALYSIS Answers given are based upon students arranging the cards in four columns and five rows. The columns colors are consistent. Students can arrange the cards in five columns and four rows and still reveal all of the patterns. Essentially, this would be like creating a periodic table that has been rotated on its side. 1. How are the first 6 cards similar? How are the cards different? Answers should include colors, symbols, shapes, and diagonals for both similar and different attributes. Numbers, size of boxes, and amount of sphere that is filled should be included with differences. 2. Do the additional 6 cards fit into your original arrangement? What patterns did you use to arrange the 12 cards? Most students will find they need to change their original arrangement to accommodate the six new cards. Patterns will include colors, diagonals, symbols, shapes, and numbers. 3. Describe the classification of your final arrangement for the 18 cards in the following manner. a. How are the cards arranged in each row? Students should include the sphere progressively filling up, the quadrant in the center box in the same position, and the center box size decreasing. b. What patterns do the cards in a column have in common? Colors are the same, the sphere is at a consistent level, and the box size increases as you move down the column. c. What exceptions to the pattern, if any, are found in your arrangement? Student answers will vary. d. List four rules that you used for the classification of your final arrangement. Colors are consistent in columns The spheres fill from left to right along the rows. The diagonal patterns are consistent (triangles, circles, stars, and x s) Box size decreases along the rows and increases down the columns (answers will be just the opposite if students pattern is rotated) 4. Predict the patterns (shapes, number, color, and so on) of the missing cards. Sketch your prediction for the two missing cards in the spaces provided. Withholding the same two cards for the entire class makes for a quick assessment. We suggest removing the two cards shown in Figure B. Figure B. Withheld cards A N S W E R K E Y vi

7 Middle Grades Science It's in the Cards CONCLUSION QUESTIONS Answers given are based upon students arranging the cards in four columns and five rows. The columns colors are consistent. Students can arrange the cards in five columns and four rows and still reveal all of the patterns. Essentially, this would be like creating a periodic table that has been rotated on its side. 1. List one pattern of the cards in the final arrangement that shows a repeating or periodic pattern for each column. The colors are the same. The level of the sphere remains constant. The box size increases. The number decreases. 2. List one pattern of the cards in the final arrangement that shows a repeating or periodic pattern for each row. The quadrant in the center box stays in the same position. The sphere fills up from left to right. The box size decreases. 3. Elements in each column of the periodic table are known as a group or family and rows are called periods. Would these names also be appropriate for your arrangement of cards? Explain. Yes, these names are appropriate. It is appropriate because they share similarities like families do whereas the periods show repeating patterns or trends. 4. The atomic radius of an element is approximately the distance between the nucleus of the atom and the outermost electron cloud. If a square on the card represents the atomic radius, then describe what happens to the atomic radius when you move from left to right along the rows and down the columns. The atomic radius decreases as you move from left to right and increases as you go from top to bottom. 5. Place your finger on the thumbnail sketch at the bottom of each card and write down the numbers that you see. Do the numbers increase or decrease as you move left to right along the rows? Do the numbers increase or decrease as you move down the columns? The numbers increase as you move from left to right and increase as you move down the columns. A N S W E R K E Y vii

8 It s in the Cards Middle Grades Science Middle It s Grades in the Science Cards Introduction to the Periodic Table MATERIALS cards, colored pattern Have you ever tried to find a specific song on itunes and you cannot remember the exact title? The songs are arranged, or classified, according to the following scheme: new releases, top ten releases, and genre (rap, country, jazz, rock, or classical). All the songs in a particular section have something in common and are arranged by some pattern, whether it is alphabetically by song title, or by artist, or numerically by trending statistics. When you go to a different section, the alphabetical arrangement is repeated along with the trending statistics. In this activity, you will arrange a set of 18 out of 20 cards in rows and columns that will display certain patterns and trends, and then predict the missing two cards. You will organize the cards in a manner that simulates the chemical solitaire that led Mendeleev to devise his Periodic Table of the Elements, which is the basis of the periodic table we use today. Periodic refers to the repeating pattern of certain properties of the elements when properly arranged. For each element Mendeleev wrote the symbol, the atomic weight, and its chemical properties on a card. Mendeleev found he could arrange the then-known elements in a table based upon increasing atomic weights and similar chemical properties. As arranged, the cards made sense whether reading across the rows or down the columns. This organization of the elements into a logical table is one of the great achievements in the history of science. However, the genius of Mendeleev was that he recognized that just as in the card game Solitaire where some of the cards are hidden, so too some of the elements were hidden or undiscovered. Mendeleev left spaces for elements that he predicted should exist but had not yet been discovered. PURPOSE In this activity, you will be provided 18 cards to arrange into rows and columns. You will formulate four rules, and then apply those rules to predict two missing cards. 1

9 Middle Grades Science It s in the Cards PROCEDURE 1. Each group will be given an envelope that contains 18 cards. Do not look at the cards until instructed to do so. When directed by your teacher, remove six cards at random and place them on the lab table in a logical order. Make observations and describe the patterns you used to organize the six cards on your student answer page. 2. When directed by your teacher, remove six more cards at random from the envelope and combine them with the previous six cards on the lab table in a logical order. Describe the patterns you used to organize the cards in vertical columns and horizontal rows on your student answer page. If a card appears to be missing, leave a space for it. 3. When directed by your teacher, remove the remaining cards from the envelope and combine them with the previous 12 cards on the lab table in a logical order. Describe the patterns you used to organize the cards in vertical columns and horizontal rows on your student answer page. Your final arrangement should include space for two missing cards. 4. Once your group has finalized the arrangement of cards, describe the resulting classification system in the Analysis section. You will formulate four rules, and note any exceptions to the pattern. 5. Predict the properties (shapes, color, number, and so on) of the two missing cards. Record your predictions on your student answer page. 6. Return the cards as instructed to your teacher. 2

10 Middle Grades Science It s in the Cards DATA AND OBSERVATIONS 6 CARDS: 12 CARDS: 18 CARDS: 3

11 Middle Grades Science It s in the Cards ANALYSIS 1. How are the first 6 cards similar? How are the cards different? 2. Do the additional 6 cards fit into your original arrangement? What patterns did you use to arrange the 12 cards? 3. Describe the classification of your final arrangement for the 18 cards in the following manner. a. How are the cards arranged in each row? b. What patterns do the cards in a column have in common? c. What exceptions to the pattern, if any, are found in your arrangement? d. List four rules that you used for the classification of your final arrangement. 4

12 Middle Grades Science It s in the Cards ANALYSIS (CONTINUED) 4. Predict the patterns (shapes, number, color, and so on) of the missing cards. Sketch your prediction for the two missing cards in the spaces provided. 5

13 Middle Grades Science It s in the Cards CONCLUSION QUESTIONS 1. List one pattern of the cards in the final arrangement that shows a repeating or periodic pattern for each column. 2. List one pattern of the cards in the final arrangement that shows a repeating or periodic pattern for each row. 3. Elements in each column of the periodic table are known as a group or family and rows are called periods. Would these names also be appropriate for your arrangement of cards? Explain. 6

14 Middle Grades Science It s in the Cards CONCLUSION QUESTIONS (CONTINUED) 4. The atomic radius of an element is approximately the distance between the nucleus of the atom and the outermost electron cloud. If a square on the card represents the atomic radius, then describe what happens to the atomic radius when you move from left to right along the rows and down the columns. 5. Place your finger on the thumbnail sketch at the bottom of each card and write down the numbers that you see. Do the numbers increase or decrease as you move left to right along the rows? Do the numbers increase or decrease as you move down the columns? 7

15 Middle Grades Science It's in the Cards ITEM 1 BLUE PERIODIC CARDS L E S S O N C O N S U M A B L E 8

16 Middle Grades Science It's in the Cards ITEM 2 GREEN PERIODIC CARDS L E S S O N C O N S U M A B L E 9

17 Middle Grades Science It's in the Cards ITEM 3 RED PERIODIC CARDS L E S S O N C O N S U M A B L E 10

18 Middle Grades Science It's in the Cards ITEM 4 YELLOW PERIODIC CARDS L E S S O N C O N S U M A B L E 11