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The Periodic Table of Elements
The purpose of this unit is to explain and demonstrate the use of the periodic table. This table was designed as a means for logically organizing and correlating the chemical elements. To better understand the chemical behavior of the elements, a working knowledge of the manner in which the elements are organized is imperative. Without this knowledge, a description of the chemical reactivity and elemental properties becomes nothing more than a list of facts, difficult to learn and soon forgotten.
This unit is designed for the eleventh grade chemistry class. Chemistry topics build upon one another and are therefore offered in sequential fashion. Thus, the periodic table unit is typically covered midway through the school year and it will last for approximately two weeks. It is designed for block scheduling where the students meet three times a week for 80-minute periods. I have made a conscious effort to incorporate instructional methods and assessment techniques that vary from the traditional “direct instruction with pencil and paper tests” that have historically been used in the chemistry classroom. By doing this, I hope to make the subject of chemistry relevant and enjoyable, moving away from rote memorization into the realm of meaningful learning.
Upon completion of this unit, the student will:
? Make connections between the science of chemistry and their lives
? Understand a periodic trend
? Understand the contributions that Meyer and Meendeleev made to the creation of the periodic table.
? Differentiate between a group and a period
? Define and locate the five main groups of elements on the periodic table
? Use the periodic table to predict properties of elements
? Demonstrate a knowledge of the terms ionization energy, electronegativity, and atomic radii
? Classify elements as metals or non-metals based on their chemical properties
Chemistry has historically been a subject feared
and avoided at all cost by many high school students. Even when agreeing
to take the course, many students find the subject matter difficult, boring,
and irrelevant to their lives. It is my hope to take the science
of chemistry and create a situation in which the students can better understand
the material, can easily see a connection between chemistry and their world,
and will ultimately have fun while learning.
Direct instruction will inevitably play a role in the chemistry course. There will be some instances where the best way to get the material across is to stand in front of the students, explaining and manipulating information. In this unit, however, I have supplemented the lecture format with discovery lessons, cooperative learning opportunities, games, journal writing, admit and exit slips, and class discussions in order to better captivate the interest of the student. In addition, I believe that these methods will ultimately produce a learning environment in which the student can learn in a personally meaningful way.
I will begin the unit with a class discussion and brainstorming session on the meaning of a periodic trend such as the daily temperature. Brainstorming is an excellent method for activating schemata, so I will use it here and throughout the unit. I will also have a graph on display that demonstrates a periodic trend for visual learners. . A demonstration of finding trends between objects will make the periodic trend easier to understand. Our discussion will then lead to the chemical elements, and suggestions for creating periodic trends of the elements will be discussed. Questioning is a big part of the unit, and it will enable the students to better make connections The history and creation of the periodic table is discussed, and I will use time lines to better describe this information. Finally, the meaning of the periodic law is described. Exit slips will be used at the end of class, at which time the students will be asked to describe in writing or picture format the meaning of the term periodic trend. Finally, for the homework assignment, the students will be asked to choose a personally relevant collection of at least 10 items and describe how they would create an organizational method for sorting these items. The items must be organized based on at least 2 criteria. For instance, an example will be given of a CD collection organized vertically by type of music and horizontally by alphabetical order. The students will be asked to comment in their journals on whether or not this system would make it easier to find a storage place for a newly purchased item.
The next step in the unit is the explanation of how to actually read the periodic table. Terms will be defined, and a pneumonic device to aid in memory of the terms used to describe the horizontal versus the vertical rows of the table will be created by the class. The location of different types of elemental properties will be colored in on a blank periodic table by the class as a whole, and each property will be related to something that the students can understand from the real world. For instance, a discussion of transition metals will ensue, iron and gold being the topic of conversation. This will link something known to something unknown, facilitating interest, motivation, and meaningful learning opportunities. Using the periodic table as a predicting device is then discussed. I will model how to predict the properties of elements based on their location in the table. The students will then get into groups and play the “property identification game”. Ten cards will be given to each group, each one listing an element, location, and properties of surrounding elements. The cards will be discussed one at a time, and the students will try to predict the elemental property in question. The completion of a study guide will be assigned for homework, and as the student completes the guide the information learned in class will be reinforced.
Lesson #3 concerns the properties of metals. This is an area where plenty of connections can be made to the real world. I will have centers set up with examples for the students to actually touch and manipulate, and as they travel from center to center I will have them make a list of the qualities they observe in the examples. We will then create a chart depicting metallic qualities that will be displayed in class for the remainder of the unit. While some qualities cannot be easily detected just by looking or by handling the material, an explanation of these will be necessary. A brainstorming session will ensue in which the students will try to make qualified statements about the characteristics of the metallic properties in the periodic table. After this discussion and clarification, we will play the koosh ball game. I will throw the ball to a student, pick an element, and ask that student what period and group the element is in, as well as whether or not it is a metal or nonmetal. They will then throw the koosh ball and repeat the process.
Admit slips will be assigned at the beginning of the next class period. The students will be asked to describe as many characteristics of a metal as possible. This will give me valuable insight into their understanding thus far.
The topic for the fourth lesson will then be introduced. The periodic trends of electronegativity, ionization energy, and atomic radii will be explained and discussed. The use of a graphic organizer will best enable the students to organize the above information in a meaningful way. I will model this procedure while describing the trends, using both a table format as well as a flow-chart. I will also draw on a blank periodic chart the periodic trends we have learned so far. The students will then break into groups and create their own rendition of the information. Any organizational method can be utilized, and presentation to the rest of the class will follow in three to four days. This assignment will be used as a performance assessment activity and a rubric will be given to provide students with an explanation of exactly what is required for this project. The graphic organizers will be used for display in the classroom for the remainder of the unit.
Finally, lesson five will be a lab activity. The students will use their knowledge of periodic trends and a list of given clues to correctly arrange elements from a scrambled periodic table. Predictions about missing values on the table will also be required. I will allow the students to work in groups of two to four to complete this performance task. After creation of their periodic table, it will be explained and justified to the remainder of the class.
These five lessons do not comprise the entire unit on the periodic table, but rather are an example of activities and assessments under development at this time. I hope to provide a choice of additional projects, for example, biography presentations on the creators of the periodic table. This project could take the form of a written book review, song or poem composition, art collage, or power point presentation. As a final review before the culminating exam I would like to construct an outline of the periodic table on the floor or wall, and have the students indicate where an element is located that is described by a particular periodic trend. I believe that these activities will incorporate student control, competency, and fun into the classroom format.
I have incorporated a variety of assessment tools into this unit to ensure that each student will be able to demonstrate what they have learned in a method that is personally meaningful. The assessment procedures will be ongoing throughout the unit. A large part of this process will be accomplished through informal performance assessments, as I observe the student’s participation in activities, class discussions, and projects. While this type of assessment can be subjective, I will consistently make written notes concerning the progress of the students, as well as their ability and willingness to participate in class. This information will prove invaluable to me, providing me with information as to the students level of understanding, and maybe more importantly their attitudes and interests towards the class. The classroom participation portion of the overall assessment will be worth 10 points.
Through the inclusion of writing assignments into the chemistry curriculum, I have tried to give the students a chance to reflect on their own learning and discoveries. I believe that if one can write and reflect about their knowledge then true learning has taken place. I will use tools such as the exit and admit slip, gaining beneficial results in a time efficient manner. By participating in this activity, the students will be able to articulate what they have learned, while I can gain insight into their progress, attitudes, and interests. These writing assignments will be confidential and will never be used in a negative manner, for instance to lower ones grade. They will simply be a tool to access information. Journal entries will be assigned periodically to give students the opportunity to make connections between chemistry and their lives. Like the admit and exit slip, these will not be assessed on content or written skill, but rather on effort and honesty of information. In order to get accuracy of information I must establish a trusting relationship with the students in respect to their writing. Only in this way will I get honest reflections. The above mentioned personal reflections will be worth 10 points in the overall assessment of the unit.
Homework will be assigned periodically to reinforce the class work. Like in a math class, practice in solving problems and analyzing information is imperative for successful understanding of material. It will not be graded for accuracy, per se, but more importantly for effort. If the student completes at least 85% of the homework they will get full credit for that assignment. These assessments will be worth 20 points in the overall assessment.
Two performance assessments will be utilized in this unit. The first will be the creation of a graphic representation of concepts discussed in the unit. In doing this the students will have an opportunity to organize the material in a personally meaningful way. They will be allowed to work in groups or individually, having been given a rubric that depicts the exact requirements of the project. The second performance assessment will be done in a lab format where the students will arrange fictitious elements in a periodic table based on their knowledge of the periodic properties and a provided list of clues. The skills of prediction and analysis play a huge role in this assessment, and once again a rubric for assessment purposes will be provided for each student. These two assessments will be worth 20 points each as I feel that they will demonstrate very clearly the level of knowledge gained by the students.
Finally, a unit test will be utilized as a culminating activity. There will be questions on the exam that will mimic those found on the Regent’s test, and in addition there will be essay questions that require a greater depth of knowledge. A complete study guide and list of important information will be provided to each student. The exam will be worth 20 points towards the final unit grade.
The most important aspect of my assessment procedure will be the explanation of the criteria used for the assessment. The students must have a thorough knowledge of what is expected of them and of exactly what knowledge is necessary for success.
Lesson One- the Periodic Trend
Upon completion of this lesson the student will be able to:
? Define the term period as used to describe a periodic trend
? Articulate in writing the meaning of a periodic trend
? Discuss how Mendeleev and Meyer helped to develop the periodic table
? Evaluate criteria for organization of personal collection using at least two variables.
? State periodic law
? Discuss examples of periodic trends; explain meaning of the term period as used to describe a periodic trend. Show the students a graph that depicts what a periodic trend looks like.
? Ask the students how the chemical elements might be organized in a similar way. Brainstorm for possible examples of meaningful organization.
? Demonstration of What’s the Trend? On the overhead projector I will place eight rectangles made form a transparency. Each has different markings and colors. I will then ask the students to help in arranging the rectangles in some logical order so that the trends can be observed among them. The students then make predications about a missing rectangle. Explain that this is an example of how the periodic table works.
? Create a time line of the history of the periodic table. Discuss the contributions made by Meyer and Mendeleev in the creation of the periodic table.
? Define periodic law. (Many properties of elements vary in a periodic way with their atomic number.) Explain that we will be studying this periodicity and using it to predict chemical properties for the next several class periods.
? Homework assignment is a journal entry in which at least ten similar items found in students home are to be classified using at least two different criteria to do so.
? Before leaving class students are asked to write an exit slip, explaining what the term periodic trend means to them.
The assessment for this lesson will be informal in nature and will be based on class participation, and on the completion of the exit slip and journal entry. As discussed previously, the content or structure of writing assignments will not be used as a grading tool. Instead the content will be used as a guide for assessing knowledge acquisition, interests and attitudes.
Lesson 2 – Reading the Periodic Table
Upon completion of this lesson the student will be able to:
? Define and distinguish between the terms group, family and period
? Create a pneumonic device to aid in memory of terms
? Accurately label blank periodic table in the five areas of alkali metals, alkaline metals, halogens, noble gases, and transition metals.
? Accurately predict physical properties of element based on its location in periodic table.
? Accurately predict formula of element in compound based on its location in periodic table.
? Students will be given a blank periodic table to use in discussion
? Using blank periodic table, explain and label the different groups and periods
? Explain that the periodic table arrangement depicts elements in order of increasing atomic number in horizontal rows. Rows are of such length that elements with similar physical and chemical properties fall directly beneath one another into groups.
? As a class, create pneumonic device to aid in memory of fact that horizontal rows are called periods and vertical rows are called groups. An example is happy people for horizontal periods and very grumpy for vertical groups.
? Using colored pencils, indicate where the five major groups of elements are located. Have students use their blank table to indicate the same.
Group 1- alkali metals
Group 2- alkaline earth metals
Group 7- halogens
Group 8- noble gases
Middle of 4,5 and 6 period-transition metals
? Explain that our most useful and familiar metals are the transition metals. Give examples of Iron Fe, Copper Cu and Gold Ag. Explain one of the qualities of the transition metals is its ability to form alloys and provide examples with compositions, i.e. 18K gold is actually 75%Au and 25% Cu, while sterling silver is 92.5% Ag and 7.5% copper. Ask if students can think of any other examples (bronze, stainless steel, steel, brass, solder, etc.)
? Demonstrate method for making predictions of physical properties as well as compound formation properties using the periodic trends of elements.
? Have students get into groups and play property identification game
? Students complete study guide as homework assignment. This will also serve as aid in preparing for unit test.
Once again, assessment is informal in nature and is based on class participation in discussions and game, as well as on homework assignment.
Using only your Regents Reference Tables:
1. Give the symbols and names of the 7 diatomic elements
2. Give the symbols and names of the 7 halogens
3. Give the symbols and names of the alkali metals
4. Give the symbols and names of the alkaline earth metals
5. Give the symbols and names of the elements in the 1st period
Lesson 3- Metals and Non-Metals
Upon completion of this lesson the student will be able to:
? List at least four qualities of metals
? Determine whether an element is a metal or non-metal by its location on the periodic table
? Explain in writing how the chemistry of metals influences your life
? Students will move throughout centers created in classroom where examples of different types of metals are displayed. Examples are frying pans, silver jewelry, brass, pewter, copper wire, lead shot, and aluminum foil. Students may handle material, creating a personal list of the characteristics they found in the substances.
? Qualities that are not readily observed are then discussed and explained, such as electrical conductivity.
? Entire class will create a final copy of the chart depicting metallic qualities. Will be used as classroom display. Metals have the following properties: high electrical conductivity, high thermal conductivity (frying pans made of Cu, Fe, Al, while their handles are made out of wood, glass or plastic), luster, ductility and malleability, readily give up electrons to become positively charged ions.
? Students will brainstorm about periodic statements that can be made concerning metallic properties of elements in periodic table. Examples will be given such as the fact that silver conducts electricity much better than copper. Why is copper used for electrical wiring instead of silver? Where are these elements located in relation to each other on table?
? Bring all of information together by explaining that metallic character increases as we move down in table and decreases as we move across from left to right.
? The koosh ball game is then played. The student who catches the ball must define the period, group and metallic nature of given element.
? For homework assignment, students will write in their journal about some way that a metallic element affects their life.
Journal entries will be assessed on effort. Further assessment on this lesson will be in game participation and ability to answer questions correctly, as well as on the individual list of characteristics created at the beginning of class. Effort will be most heavily noted, as opposed to correctness of answers.
Lesson 4- Trends in Properties of Atoms
Upon completion of this unit the student will be able to:
? Define and distinguish between the following terms: ionization energy, electronegativity, and atomic radii.
? Analyze the periodic trends of ionization energy, electroneagativity and atomic radii, as they relate to metallic properties
? Create a graphic representation of the above periodic trends
? Present graphic organizer to class
? Teacher will first ask if anyone would like to share their journal entries with class
? Admit slips are then assigned, asking students to write down as many properties of metals that they can remember.
? Teacher will model creation of graphic representation of ionization energies, electornegativity, and atomic radii, depicting also how these relate to metallic qualities
? Show on blank periodic chart how the different trends are displayed
? Students will create graphic representation of periodic trends in groups
? Students will share with class
Graphic representations and presentations will be assessed according to pre-designed rubric. Students will be knowledgeable about rubric criteria before and during assessment. Journal entries and admit slips will be assessed as previously discussed.
Lesson 5- Lab Activity
Upon completion of this lesson the student will be able to:
? Accurately arrange elements from a scrambled periodic table using knowledge of periodic properties and a list of clues.
? Predict the missing properties of each element based on location in the table
? Explain the trends of properties in families and periods
? Students can work in groups of two to four, or they may work independently if they wish
? See Handout
Performance will be judged by rubric scale. Students will be knowledgeable of rubric criteria before and during the performance assessment.
Dorin, Demmin, and Gabin. (1990). Chemistry: the Study of Matter. New
Jersey: Prentice Hall.
Masterton, Sloweinski, Walford. (1980). Chemistry. New York: Holt, Rinehart
Teague,R., Wygoda, L. (1995). Performance-Based Chemistry: Developing
Assessment Strategies in High School Chemistry. Journal of Chemical Education, 72(10), 909-911.