HISD LESSON PLANNING GUIDE Lesson: Periodic Table – Organizing the Elements MASTERY FOCUS (PL‐2, PL‐3, I‐1, I‐6) Essential Understanding: When the elements are ordered by atomic number (which is nearly, but not exactly, correlated to atomic mass) periodic (repeating) patterns in their chemical and physical properties emerge. Historically, Dmitri Mendeleev used these repeating patterns to organize the elements into the Periodic Table. The patterns in chemical and physical properties can be used to predict the properties of other elements. Standards: What will students know, understand, and be able to do? TEKS 126.(5) The student understands the historical development of the Periodic Table and can apply its predictive power. The student is expected to: (A) explain the use of chemical and physical properties in the historical development of the Periodic Table. (B) use the Periodic Table to identify and explain the properties of chemical families, including alkali metals, alkaline earth metals, halogens, noble gases, and transition metals. ELPS 3. E, H. Students will discuss the patterns they see in the physical and chemical properties of elements with their cooperative learning groups and explain their rationale for organizing the elements to each other and the teacher. CCRS Science VII. Chemistry C. 1. Know the organization of the Periodic Table. C. 2. Recognize the trends in physical and chemical properties as one moves across a period or vertically through a group. Key Vocabulary: What key terms will my students need to understand? Periodic, Periodic Table, period, group, family, atomic number, main group (representative) elements, transition elements (transition metals), alkali metals, alkaline earth metals, halogens, noble gases, physical property (review), chemical property (review) Assessment Plan: How will I assess prior knowledge? How will I know my students mastered standards? (Prior Knowledge) Circulate amongst groups during the engage prediction, taking note of student predictions. Some may use prior knowledge from a previous class that lithium and potassium are in the same group to justify a prediction that they’d behave similarly. After students observe element samples, ask them to write one physical property of lithium on their white board and hold up for your inspection. Repeat with a chemical property. (Standards Mastery) Have each student create their own element card for one of the following: strontium, cesium, barium, or iodine as an exit ticket including the name of the group to which it belongs. LESSON CYCLE (I‐1, I‐4, I‐5, I‐6, I‐8) How will I engage my students in learning? How will I lead my students to mastery? CHECKS FOR UNDERSTANDING (I‐2) 1 Engage (Day 1 ‐ 8 min): Play (or perform) the Element Song by Lehrer (3 min) Predict (5 min): Which of these elements would you predict have the most similar physical and chemical properties? Why? Have students report out. 2 Explore/Explain 1 (Day 1 ‐ 35 min): Have students use their white boards to identify a physical property and a chemical Rotate element samples to student groups for student observation and property of one of the elements they’ve studied. recording. Confirm or disprove student prediction from Engage. Explore (25 min): Explain (10 min): Discuss student predictions and whether they were proved or disproved. Discuss correct answer to engage. Establish atomic mass as a poor predictor This lesson planning guide is designed to support HISD teachers in using the HISD Curriculum Planning Guides to plan daily lessons that meet the criteria outlined in the HISD Instructional Practice Rubric. The guide is not intended as a template teachers are expected to complete for their lesson planning on a daily basis. Teacher teams might consider using the guide to help them collaborate in lesson planning. HISD LESSON PLANNING GUIDE of element behavior. Pose driving question for next Explore (Is there any way we can make predictions about how an element will behave and which elements will be similar to each other? If so, how?) 3 Explore/Explain 2 (Day 2 ‐ 45 min): Actively circulate the classroom observing Students perform the card sort activity to organize the elements into the students’ work. Assist individuals as Periodic Table. Groups take a picture of their organized table to email the needed when they appear stumped. Ask teacher to facilitate reporting out in the circle discussion. as many questions as possible so the students do as much thinking as possible. Explain (15 min): Circle the wagons and have students report out on how and why they Show groups’ Periodic Table pictures via organized the table as they did. When they state scientific concepts with projector. Have students report out on everyday language, provide the appropriate content vocabulary (such as why they organized the table the way that periodic, period, group, family, atomic number). Students should have discovered that properties repeat in a periodic fashion, that some elements they did. need to be placed out of mass order to preserve the pattern, and that blank spaces should be left for undiscovered elements if one appears missing from the pattern. Discuss group and period trends in reactivity and valence. Explore (30 min): 4 Elaborate (Day 3 – 40 min): Actively circulate the classroom observing Groups are given the challenge to create a card for the “missing” element students’ work and check end product for they identified and to find room for the transition metals that were left out. correctness. They make room for the transition metals. They then read a passage about Dmitri Mendeleev and make connections between what they have done in organizing the periodic table and what he did historically. 5 Evaluate (Day 3 ‐ 5 min): Reveal the Periodic Table. Have students create an element card for strontium, cesium, barium, or iodine as an exit ticket including the name of the group to which it belongs. DIFFERENTIATION (I‐3) How will I scaffold and/or accelerate learning? For whom? How will I group my students? SCAFFOLD: Point out the different numbers of chlorine in the compounds on the cards as a guide to finding similar elements and to help identify the repeating pattern that should define the periods in their table. ACCELERATE: Have students find other organizations of the elements online. GROUP: For groups of 3 ‐ 4 LOGISTICS (I‐6, I‐10) What materials, resources, and technology will I need to prepare and arrange? 
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One set of element cards per group One blue, one pink, and one green highlighter per group At least one pair of scissors per group Set of POGIL cups per group (red, green, yellow) A whiteboard, dry erase marker, and eraser per group Pencils Computer and projector for the element song and YouTube video Camera for pictures of groups’ Periodic Tables Element samples for each element card in baskets for ease of rotation (pictures if samples aren’t available; empty glass vials can be used for all clear and colorless gases) Periodic Table bookmarks for each student (copied from included pdf or ordered from SK Science Kit and Boreal Laboratories (http://sciencekit.com/periodic‐table‐bookmarks/p/IG0047294/)Element samples Copies of activity sheets This lesson planning guide is designed to support HISD teachers in using the HISD Curriculum Planning Guides to plan daily lessons that meet the criteria outlined in the HISD Instructional Practice Rubric. The guide is not intended as a template teachers are expected to complete for their lesson planning on a daily basis. Teacher teams might consider using the guide to help them collaborate in lesson planning. Name: ____________________________________ Organizing the Elements Engage Think: Element property prediction The relative masses of atoms of each element have been determined experimentally. Atoms of argon have a mass of 39.95 atomic mass units (a.m.u.), a potassium atom has a mass of 39.10 a.m.u., and a lithium atom has a mass of 6.94 a.m.u. 1. Which of these elements would you predict have the most similar physical and chemical properties? 2. Why? Explore 1 Observe: Elements  Observe the samples of various elements at your table. On the sheets of element cards, write the state of matter and general appearance of each element in the upper right hand corner of the card, as shown in the example below.  When you have finished with the elements at your table, pass your samples to the next numbered table. The numbered table before you will pass their samples to you so that you can observe those elements, too. This will continue until you have recorded information for each of the elements for which you have a card (except gallium).  Pay special attention to the samples of argon, lithium, and potassium in order to check the prediction you made above. solid
dark grey
metal
RECORD OBSERVATIONS reacts slowly FeCl3
HERE with oxygen Fe
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Explore 2 Investigate: Element Properties Can we find patterns in the properties of the elements or organize them in some way that would make predicting physical and chemical properties of the elements possible? Activity Instructions/Questions 1. Cut out your element cards and arrange them in one long row on your table in order of increasing mass (your card for gallium doesn’t have a mass printed on it, so set it aside for now). 2. Once you’ve done this, number the cards in order (1, 2, 3…) in pencil to make it easy to return the cards to this order if they get mixed up. Be sure that you don’t take the cards out of their numerical (1, 2, 3...) order for the rest of the activity unless you have a really good reason to do so! 3. Find your card for helium and draw a circle around the element symbol in pencil. Study the card. Look for any other elements that share many of helium’s properties. Draw a circle around their element symbols in pencil. 4. Find your card for lithium and draw a square around the element symbol in pencil. Study the card. Look for any other elements that share many of lithium’s properties. Draw a square around their element symbols in pencil. 5. Find your card for fluorine and draw a triangle around the element symbol in pencil. Study the card. Look for any other elements that share many of fluorine’s properties. Draw a triangle around their element symbols in pencil. 6. Once the teacher has checked over your work, highlight the element symbols you circled in green, the symbols you squared in pink, and the symbols you triangled in yellow. Do you notice any general pattern in the ordering of the elements you highlighted? If yes, please describe below. 7. Are there any exceptions to the general pattern(s) you described above? If yes, please describe below. 8. Your cards stop at krypton. The next most massive element is rubidium. What predictions could you make about rubidium’s physical and chemical properties based on the patterns you’ve noticed? 9. Based on all the information you have gathered, something about the order of your cards should look like it needs “fixing.” What is it and how could you fix it? 10. Keeping the cards in the same order in which you have them currently, break up your long row of cards into several smaller rows, stacking the rows on top of each other so that similar elements are arranged into vertical columns. If you “read” your cards from top left to bottom right (like you would read words on a page), they should still be in numerical order (1, 2, 3…). 11. Were there any “problems” that occurred when you organized the cards in this way? If so, describe them and explain how you decided to settle them. 12. Look at the other vertical columns in your arrangement that you have not color coded. Do they share similarities with each other as well? Explain. 13. Do any of the properties of the elements within the same vertical column change in a predictable way? Explain. 14. Look at the horizontal rows in your arrangement. Do any of the properties of the elements within the same horizontal row change in a predictable way? Explain. Elaborate Periodic Table: Then and Now How does the Periodic Table you’ve constructed compare to the first Periodic Table? How does it compare to the modern Periodic Table? Part 1: Now 1. Arrange your deck of element cards back into the table you created in the previous activity. 2. Cut out the sheet of new elements you’ve been given. Decide as a group where they should fit in the Periodic Table you’ve created and adjust your table to include them. Explain your reasoning below. 3. You should have the card for gallium placed in your table, but the card is blank. Predict what should be written on the card so that it contains all the same kinds of information as is on the other element cards and write it on the card in pencil. 4. Look at the bookmark your teacher gave you. What are the new elements you included in your table called? 5. Your bookmark contains many more elements than the Periodic Table you’ve constructed so far. How has the Periodic Table on the bookmark been adjusted to accommodate the additional elements? 6. What reasoning do you think the creators of the Periodic Table on the bookmark used when they decided where to place the additional elements? Did they obey any general rules? Part 2: Then Follow the link below to the American Institute of Physics site “Marie Curie and the Science of Radioactivity” and have your Reader read the section titled “The Periodic Table of Elements” aloud to the group. Be sure to read the quotes and picture captions as well as the main text. As a group, answer the questions that follow. http://www.aip.org/history/curie/periodic.htm 1. Who is credited with the creation of the Periodic Table? 2. When was the first Periodic Table published? 3. About how many elements were known at the time of the first Periodic Table’s publication? 4. Name at least two similarities between how the first Periodic Table was developed and how your group developed your version of the Periodic Table. 5. Consider the quote at the end of the reading passage by British novelist C.P. Snow. What do you think he means? Teacher Notes: Organizing the Elements One and a half 90‐minute lessons or three 45‐minute lessons TEKS CHEM.5A Explain the use of chemical and physical properties in the historical development of the Periodic Table. CHEM.5B Use the Periodic Table to identify and explain the properties of chemical families, including alkali metals, alkaline earth metals, halogens, noble gases, and transition metals. College and Career Readiness Standards CCRS VII.C.1 Know the organization of the Periodic Table. CCRS VII.C.2 Recognize the trends in physical and chemical properties as one moves across a period or vertically through a group. English Language Proficiency Standards (ELPS) 3. E,H Students will discuss the patterns they see in the physical and chemical properties of elements with their cooperative learning groups and explain their rationale for organizing the elements to each other and the teacher. Key Questions How can we predict the properties of an element? What about the atom determines what the properties of an element will be? Prerequisites 
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Matter and Change Unit Dalton’s Atomic Theory (atomic nature of matter) Instructional Considerations 
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Ideally, this lesson should be the students’ first experience with the Periodic Table during the school year. By creating it for themselves, students will discover the patterns in element properties that are the basis for the modern Periodic Table and will be primed to recognize the empirical evidence for an electronic shell model of the atom which will be developed later. This lesson is designed for cooperative learning groups. It is assumed that the teacher would have previously grouped students and assigned roles (Suggestions: project manager, communications officer, materials officer). Also, it is designed in a POGIL style that includes mandatory check‐in points with the teacher at stop signs. Groups should have ample room in which to work. They will need a long space in order to line up their element cards in one row. Materials 
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One set of element cards per group One yellow, one pink, and one green highlighter per group At least one pair of scissors per group Set of POGIL cups per group (red, green, yellow) A whiteboard, dry erase marker, and eraser per group Pencils Computer and projector for the element song and YouTube video Element samples for each element card in baskets for ease of rotation (pictures if samples aren’t available; empty glass vials can be used for all clear and colorless gases) Periodic Table bookmarks for each student (copied from included pdf or ordered from SK Science Kit and Boreal Laboratories (http://sciencekit.com/periodic‐table‐bookmarks/p/IG0047294/). Engage (Day 1: 8 minutes) Play (or perform) the Element Song by Tom Lehrer (pick one): Flash animation version: http://www.privatehand.com/flash/elements.html Daniel Radcliffe (Harry Potter) version on The Graham Norton Show: http://www.youtube.com/watch?v=rSAaiYKF0cs Discuss the Song 
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Ask students what the lyrics of the song were (the elements). Mention how difficult it would be for chemists to memorize all of the elements and their properties. Wouldn’t it be nice to easily access information about an unfamiliar element and to be able to predict its properties without having to memorize them? Let’s see if we can find any similarities between the elements that would allow us to categorize them or predict their characteristics in any way. Direct students to complete the element prediction question with their group. Think: Element property prediction The relative masses of atoms of each element have been determined experimentally. Atoms of argon have a mass of 39.95 atomic mass units (a.m.u.), a potassium atom has a mass of 39.10 a.m.u., and a lithium atom has a mass of 6.94 a.m.u. 1. Which of these elements would you predict have the most similar physical and chemical properties? Argon and potassium 2. Why? Their atoms are almost the same mass, while an atom of lithium is much lighter, so it seems like an argon atom and potassium atom must be the most similar. If the atoms are the most similar, then their properties should also be similar. Discuss student predictions without revealing the correct answer yet. Introduce and guide the Explore 1 activity. 
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Have groups write their prediction on their whiteboards to report out. If students predict that potassium and lithium are most similar based on prior knowledge, ask them to consider the question from an historical perspective. If no one had discovered the chemical concepts they used in their reasoning before, what would they predict and why? You may wish to set a timer to signal when elements should be rotated. Explore 1 (Day 1: 25 minutes) Observe: Elements 
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Observe the samples of various elements at your table. On the sheets of element cards, write the state of matter and general appearance of each element in the upper right hand corner of the card, as shown in the example below. When you have finished with the elements at your table, pass your samples to the next numbered table. The numbered table before you will pass their samples to you so that you can observe those elements, too. This will continue until you have recorded information for each of the elements for which you have a card (except gallium). Pay special attention to the samples of argon, lithium, and potassium in order to check the prediction you made above. Explain 1 (Day 1: 10 minutes) Readdress the engage question and review physical and chemical properties. 
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NOTE: If using the sample of lithium available in the Flinn element set, students will most likely describe it as a black solid. If you’d like, showing them a brief video of the cutting of lithium (such as the one available here: http://www.youtube.com/watch?v=Mdh7cLhqNH8) can help clarify it as a shiny, silvery, and soft solid. Ask groups questions about the activity and have them use whiteboards to report out their answers. Example questions: o Describe a physical property of silicon. o Describe a chemical property of bromine. (These serve to assess their prior knowledge, reinforce these concepts, and to draw their attention to the rest of the information on their cards besides what they have directly observed). o What two elements from our engage question are most similar to each other? o How are they similar? (Make sure that similarities in printed properties like reactivity with water and compound formation with one chlorine atom are mentioned as well.) o Are these the elements you predicted would be most similar? o What does this result mean? (Example student response: “Elements with similar mass aren’t necessarily similar after all, so we can’t use mass to predict what an element will be like.”) Introduce and guide the Explore 2 activity. 
“We would still like to be able to predict what an element will be like, but apparently we can’t use the mass to do that. Is there any other way we can make predictions about how an element will behave and which elements will be similar to each other? What is it about the atom that determines what the element is like? We should try to answer those questions by looking more closely at the information we’ve compiled about the elements we’ve seen.” Explore 2 (Day 2: 30 minutes) Investigate: Element Properties Can we find patterns in the properties of the elements or organize them in some way that would make predicting physical and chemical properties of the elements possible? Activity Instructions/Questions 1. Cut out your element cards and arrange them in one long row on your table in order of increasing mass (your card for gallium doesn’t have a mass printed on it, so set it aside for now). 2. Once you’ve done this, number the cards in order (1, 2, 3…) in pencil to make it easy to return the cards to this order if they get mixed up. Be sure that you don’t take the cards out of their numerical (1, 2, 3...) order for the rest of the activity unless you have a really good reason to do so! (make sure the cards are really in one long row) 3. Find your card for helium and draw a circle around the element symbol in pencil. Study the card. Look for any other elements that share many of helium’s properties. Draw a circle around their element symbols in pencil. (circles should be drawn around helium, neon, argon, and krypton) 4. Find your card for lithium and draw a square around the element symbol in pencil. Study the card. Look for any other elements that share many of lithium’s properties. Draw a square around their element symbols in pencil. (squares should be drawn around lithium, sodium, and potassium) 5. Find your card for fluorine and draw a triangle around the element symbol in pencil. Study the card. Look for any other elements that share many of fluorine’s properties. Draw a triangle around their element symbols in pencil. (triangles should be drawn around fluorine, chlorine, and bromine) 6. Once the teacher has checked over your work, highlight the element symbols you circled in green, the symbols you squared in pink, and the symbols you triangled in yellow. Do you notice any general pattern in the ordering of the elements you highlighted? If yes, please describe below. The colored cards are always in clumps. Pink cards usually come after green cards. Yellow cards usually go before green cards. 7. Are there any exceptions to the general pattern(s) you described above? If yes, please describe below. Hydrogen looks like it should be yellow so that there’d be a yellow, green, pink at the beginning. In one of the clumps, it goes yellow, pink, green instead of yellow, green, pink (chlorine, sodium, argon). 8. Your cards stop at krypton. The next most massive element is rubidium. What predictions could you make about rubidium’s physical and chemical properties based on the patterns you’ve noticed? It reacts violently with water. It forms RbCl. It’s a solid metal. 9. Based on all the information you have gathered, something about the order of your cards should look like it needs “fixing.” What is it and how could you fix it? Argon looks like it should come before potassium even though it’s heavier. We should swap those two cards. 10. Keeping the cards in the same order in which you have them currently, break up your long row of cards into several smaller rows, stacking the rows on top of each other so that similar elements are arranged into vertical columns. If you “read” your cards from top left to bottom right (like you would read words on a page), they should still be in numerical order (1, 2, 3…). 11. Were there any “problems” that occurred when you organized the cards in this way? If so, describe them and explain how you decided to settle them. Hydrogen doesn’t fit into any group very easily. It forms compounds with only one chlorine, so it is similar to both the pink and yellow groups, but doesn’t perform the same kind of reactions. We put it in the pink group because that’s where we remembered it being in the real periodic table. Also, it looks like there’s an element missing between calcium and germanium. There should be an element that forms a compound with three chlorines there, so we skipped a spot to keep germanium under the rest of the four chlorine compounds. 12. Look at the other vertical columns in your arrangement that you have not color coded. Do they share similarities with each other as well? Explain. Yes. They mostly perform the same kind of reaction, they just differ in how vigorously they react. Also, they all form compounds with the same number of chlorine atoms. 13. Do any of the properties of the elements within the same vertical column change in a predictable way? Explain. Yes, in the pink groups and other groups on the left side of the arrangement, the elements get more and more reactive as you go down the column. In the yellow groups and other groups on the left (except for the green group), the elements get less reactive as you down the column. 14. Look at the horizontal rows in your arrangement. Do any of the properties of the elements within the same horizontal row change in a predictable way? Explain. Yes, the number of chlorines in the compounds formed with each element counts up and back down (1 – 2 – 3 – 4 – 3 – 2 – 1 – 0). Explain 2 (Day 2: 15 minutes) Discuss Explore 2. 
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Have groups take a picture of their table and email it to you so that you can display them to the class. Have students “circle the wagons” to facilitate a group discussion of the activity. Show the pictures of the groups’ tables and encourage them to ask questions of each other or make comments based on what they see. Students may have arranged the tables slightly differently (i.e. hydrogen over the halogens or noble gases as the first column). Have them explain their rationale to each other. Without further information, there’s really no good reason why the noble gases should be at the end of the periodic table instead of the beginning, for example. Therefore, honor the differing interpretations so long as they keep similar elements in groups and the elements generally in increasing mass order. Evidence that supports the alkali metals coming first will be provided in a later lesson. However, you can ask that everyone arrange their table to put the “pink group” first so that there’s consistency in the class discussion. 
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Be sure to discuss their placement of gallium (or their leaving a blank space between calcium and germanium), the swapping of argon and potassium, and the trends they noticed in reactivity and valence (bonding with chlorine). o Example Dialogue: Let’s remind ourselves of questions we were hoping to answer. The first one was, “Is there any way we can make predictions about how an element will behave and which elements will be similar to each other?” What do you guys think? Have we answered this question? If so, what’s the answer? Yeah. The properties of the elements kind of repeat in a pattern, so you kind of know what an element will be like depending on where it is in the pattern. Like, we were able to predict that rubidium would explode if it was put in water because it would fit under potassium. Great! You said the properties of the elements repeat in a pattern. In chemistry terms, we say that the elements tend to exhibit “periodicity” when ordered according to mass. Since the elements are arranged in a kind of table, we call the arrangement of the elements you just made a “periodic table.” Each row of the table is one full cycle of the pattern, so it is called a period. (etc…) As concepts come up in discussion, provide the appropriate chemistry vocabulary to describe them. For example, when students comment that similar elements are in columns, provide the information that vertical columns are called groups or families and instruct them to write this definition in their notebook. When they refer to the “pink group,” describe those elements as the alkali metals, etc. Vocabulary that should be addressed in this discussion includes: o Period o Periodic Table o Periodicity o Group/family o Alkali metals o Alkaline earth metals o Halogens o Noble gases o Atomic number (Although, at this point, protons have not been “discovered.” The atomic number should just be defined as the rank order of the elements in the Periodic Table for now.) Ask groups to report out their predictions for rubidium using their whiteboards. Show the video http://www.youtube.com/watch?v=t2uwzNZAp‐s. Define the Periodic Law: The physical and chemical properties of the elements are a periodic function of their atomic number. Elaborate (Day 3: 40 minutes) Introduce and guide the Elaborate activity. (30 minutes) 
“You all have started creating a Periodic Table and have explained to me how it can be used to predict what an element will be like, but our table isn’t complete. There are many more elements in addition to the ones we’ve looked at already. Also, how does our creation of the Periodic Table 
compare with the historical development of the Periodic Table? You all will work in your groups to answer these questions and elaborate on what you’ve learned so far.” Give each group a sheet of transition metal cards and their “Elaborate” sheet. Periodic Table: Then and Now How does the Periodic Table you’ve constructed compare to the first Periodic Table? How does it compare to the modern Periodic Table? Part 1: Now 1. Arrange your deck of element cards back into the table you created in the previous activity. 2. Cut out the sheet of new elements you’ve been given. Decide as a group where they should fit in the Periodic Table you’ve created and adjust your table to include them. Explain your reasoning below. (Cards should be in mass order between calcium and gallium – or the blank space where gallium should go. You can choose to reveal to them that Co comes before Ni despite the fact that Co is slightly heavier if you wish. If you do so, make sure they understand that it is to preserve a pattern that they cannot see yet because they don’t have the elements that come after krypton to work with.) 3. You should have the card for gallium placed in your table, but the card is blank. Predict what should be written on the card so that it contains all the same kinds of information as is on the other element cards and write it on the card in pencil. solid
silvery
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does not react GaCl3 with oxygen Once you have confirmed their order and their predictions for gallium, give each student a Periodic Table bookmark that shows the long version of the Periodic Table. Ga
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4. Once your teacher has confirmed your card placement, change the atomic numbers you wrote on your cards as needed to reflect the new order. 5. Look at the bookmark your teacher gave you. What are the new elements you included in your table called? Transition metals 6. Your bookmark contains many more elements than the Periodic Table you’ve constructed so far. How has the Periodic Table on the bookmark been adjusted to accommodate the additional elements? Their Periodic Table contains more rows (periods) and they created a gap between Ca and Sc to fit more elements in period 6 and 7. 7. What reasoning do you think the creators of the Periodic Table on the bookmark used when they decided where to place the additional elements? Did they obey any general rules? They kept placing the elements in roughly increasing mass order and kept similar elements on top of each other in columns (families). That meant splitting the table again like we did to fit Sc – Zn in order to fit Ce – Lu and Th – Lr. Part 2: Then Follow the link below to the American Institute of Physics site “Marie Curie and the Science of Radioactivity” and have your Reader read the section titled “The Periodic Table of Elements” aloud to the group. Be sure to read the quotes and picture captions as well as the main text. As a group, answer the questions that follow. http://www.aip.org/history/curie/periodic.htm 1. Who is credited with the creation of the Periodic Table? Dmitri Mendeleev 2. When was the first Periodic Table published? 1869 3. About how many elements were known at the time of the first Periodic Table’s publication? A little over 60 4. Name at least two similarities between how the first Periodic Table was developed and how your group developed your version of the Periodic Table. 1. Mendeleev wrote properties of the elements on cards and moved them around to organize them like we did. 2. He left gaps in his table to leave room for undiscovered elements like we did with gallium. 3. He predicted what an unknown element would be like based on where it should fit in the table like we did. 4. He swapped a few elements to keep them in the right spot in the pattern even though it messed up the mass order a bit like we did. 5. Consider the quote at the end of the reading passage by British novelist C.P. Snow. What do you think he means? I think he means that there are a lot of elements and they all have a lot of different properties which can be confusing and hard to keep track of, but that the Periodic Table organizes them so that they all make sense and you can see patterns. Discuss the Elaborate activity. (10 minutes) 
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Have students report out key answers from the activity. Show students a modern Periodic Table (such as the one at ptable.com). If you have a large one for hanging in your room, now would be a good time to hang it up or reveal it. It would also be a good time to hand out student copies of official Periodic Table reference sheets they will have access to during the school year. Ask students how the modern Periodic Table is different from the one on the bookmark. (Lanthanides and Actinides are at the bottom instead of inside the rest of the table.) Ask students why they think they are there. (The Periodic Table is really long with them inserted in the table which makes it hard to print on a sheet of paper. Putting them at the bottom is just a matter of convenience.) Point out all other relevant issues in Periodic Table “geography” that haven’t already come up (like, where the metals are, where the nonmetals are, where the metalloids are, the names for the Lanthanides and Actinides, etc.) “There were two questions we wanted to answer about the elements and their properties when we began our investigation into the Periodic Table. First we wanted to know if there was a way to predict what an element will be like. You’ve answered that one. (you may want a student to answer this question again as a summary of what they’ve learned). The second question was what is it about the atom that determines what the element is like? Can we explain why there’s a repeating pattern in the properties of the elements?” (No.) “You’re right. We still don’t have enough information to answer that question. We’ll have to make more observations and analyze more data before we can draw any conclusions about that.” Evaluate (Day 3: 5 minutes) Have students each make an element card using a blank note card. They can all be assigned the same element or different elements. Some options include: strontium, cesium, barium, iodine, xenon, etc. Have them indicate to what family the element belongs and whether it is a metal or nonmetal on the card as well.