Chemical Nomenclature

Transcription

1 Chemical Nomenclature Chemistry Unit: 05 Lesson: 01 Suggested Duration: 12 days Lesson Synopsis: In this lesson, students will discover the importance of having a common and consistent system of rules for writing formulas and naming chemical compounds. The lesson will focus upon developing an understanding of how to write formulas and name compounds appropriately. Models will be used to aid students understanding and application of the International Union of Pure and Applied Chemistry (IUPAC) rules for chemical nomenclature. TEKS: C.7 Science concept. The student knows how atoms form ionic, metallic, and covalent bonds. The student is expected to: C.7A C.7B Name ionic compounds containing main group or transition metals, covalent compounds, acids, and bases, using International Union of Pure and Applied Chemistry (IUPAC) nomenclature rules. Readiness Standard Write the chemical formulas of common polyatomic ions, ionic compounds containing main group or transition metals, covalent compounds, acids, and bases. Readiness Standard Scientific Process TEKS: C.2 Scientific processes. The student uses scientific methods to solve investigative questions. The student is expected to: C.2D C.2E C.2F C.2H C.2I Distinguish between scientific hypotheses and scientific theories. Plan and implement investigative procedures, including asking questions, formulating testable hypotheses, and selecting equipment and technology, including graphing calculators, computers and probes, sufficient scientific glassware such as beakers, Erlenmeyer flasks, pipettes, graduated cylinders, volumetric flasks, safety goggles, and burettes, electronic balances, and an adequate supply of consumable chemicals. Collect data and make measurements with accuracy and precision. Organize, analyze, evaluate, make inferences, and predict trends from data. Communicate valid conclusions supported by the data through methods such as lab reports, labeled drawings, graphs, journals, summaries, oral reports, and technology-based reports. GETTING READY FOR INSTRUCTION Performance Indicator(s): Given a set of 3 5 elements, write the names and formulas of several ways that the elements might combine to make compounds and/or polyatomic ions. Select two compounds to explain, orally and in writing, how and why the compound can be made from a given set of elements. (C.2F, C.2I; C.7A, C.7B) 5B, 5F Key Understandings and Guiding Questions: Atoms of different elements combine in definite proportions to form compounds that are represented by chemical formulas. How are elements combined to make chemical compounds? All compounds are named in such a way that people can understand the atomic makeup of the compounds. Why is it important that there is a consistent way to name chemical compounds? What information can be derived from the name of a compound? Vocabulary of Instruction: ion anion cation oxidation number ionic compound law of definite proportions chemical formula molecule IUPAC (International Union of Pure and base 2012, TESCCC 06/17/13 page 1 of 14

2 Refer to section for materials. Attachments: Handout: Common Compounds (1 per student) Teacher Resource: Common Compounds KEY Handout: Blank Periodic Table (1 per student) Teacher Resource: Ion Cards (see Advance Preparation, 1 per student and 1 set for projection) Handout: Naming Compounds Practice Problems (1 per student) Teacher Resource: Naming Compounds Practice Problems KEY Handout: Writing and Naming Ionic Compounds (1 per student) Teacher Resource: Writing and Naming Ionic Compounds KEY Teacher Resource: Formulas for Ionic Compounds Station Card (1 per station) Teacher Resource: Formulas for Ionic Compounds Sample Data Table Teacher Resource: Formulas for Ionic Compounds Sample Data Table KEY Teacher Resource: Formulas for Ionic Compounds Teacher Instructions and KEY Teacher Resource: Prefixes for Binary Molecular Compounds (see Advance Preparation, 1 card per student) Handout: Element Cards PI (1 card per student) Teacher Resource: Performance Indicator Instructions KEY Advance Preparation: 1. Prior to Day 1, obtain an empty, clean container of each of the following household products and obtain an MSDS for each container. Note: More complex household substances will be used as a follow up during the Elaborate II activity. bottle of water box of caustic soda (lye or drain cleaner) box of baking soda bottle of bleach bottle of rubbing alcohol bag or box of sugar cubes or sugar box of table salt 2. Prior to Day 3, print and cut out a copy of the Teacher Resource: Ion Cards for projection. Additionally, print a copy of the handout for each student, on 8.5 x 11 cardstock if available. They will cut these out in class. If you use an overhead projector, you will need transparencies for the modeling process. If you use a document projector, you will need paper copies. 3. Prior to Day 6, prepare dilute solutions (0.1 M) of several acids and bases for the investigation: Formulas for Ionic Compounds. Prepare solutions in 24 dropper bottles or small disposable cups. Label each ONLY with the ION in parentheses as follows: 1 silver nitrate (Ag +1 ) 1 lead (II) nitrate (Pb +2 ) 1 copper (II) sulfate (Cu +2 )

3 1 magnesium sulfate (Mg +2 ) 1 iron (III) chloride (Fe +3 ) 2 iron (III) chloride (Cl -1 ) 2 potassium iodide (I -1 ) 5 sodium hydroxide (OH -1 ) 5 sodium carbonate (CO 3-2 ) 5 sodium phosphate (PO 4-3 ) Refer to the Teacher Resource: Formulas for Ionic Compounds Teacher Instructions and KEY for placement of the materials at each station. Each group will move through five stations, so prepare materials accordingly. 4. Prior to Day 8, conduct an Internet search on dihydrogen monoxide (DHMO) to determine which dangers you want to present to the class. You may choose to use different ones with different classes. Note that DHMO is an example of an elaborate hoax. 5. Prior to Day 8, copy and cut apart cards from the Teacher Resource: Prefixes for Binary Molecular Compounds. You will need one card per student. 6. Prior to Day 9 Gather diluted acids and bases for teacher demonstration. Obtain an empty, clean container of each of the following (more complex) household products and an MSDS for each container if possible. For safety purposes, use only the clean, empty container. cooking oik vinegar baking powder window cleaner detergent cereal vitamins other cleaning products 7. Prepare attachment(s) as necessary. Background Information: The International Union of Pure and Applied Chemistry (IUPAC) is the organization responsible for systemizing chemical nomenclature worldwide. It has published a series of books in many different chemical nomenclature areas (e.g., for inorganic, physical, and organic chemistry). A summary of the basic IUPAC rules, as they apply to ionic and covalent compounds and acids and bases, follows. NOTE: A chemical name should be unambiguous with regard to the chemical formula it denotes and vice versa, and in organic chemistry, for example, to its structure as well. High school chemistry students (and their teachers) need to know common (a.k.a. "trivial") as well as systematic names of many compounds. Polyatomic ion names, formulas, and charges are included in the STAAR Chemistry Reference Materials. Rule 1: Naming Simple Ionic Compounds. Ionic compounds are made up of one or more cations (positive ions) and one or more anions (negative ions).

4 The first part of the ionic compound name is always the cation, usually a metal ion, such as sodium (Na). If the metal can have more than one oxidation state, such as iron (Fe), then Roman numerals in parentheses are used to indicate the different oxidation numbers, such as Fe(II) and Fe(III). The second part of the ionic compound name is always the anion. o If it is a single non-metal anion, such as chlorine (Cl), then the end of the ion name is changed to ide (chloride). o If it is a polyatomic anion, then the name of the anion is used.. Some polyatomic anions contain oxygen. These anions are called oxyanions. It is possible for an element to form more than one oxyanion. When an element forms two oxyanions, the one with less oxygen is given a name ending in -ite and the one with more oxgyen is given a name that ends in ate. For example, sulfite (SO 3- ) and sulfate (SO 4- )). When an element can form four oxyanions, the hypo- and per- prefixes are used in conjunction with the -ite and -ate suffixes. The hypo- and per- prefixes indicate less oxygen and more oxygen, respectively. For example, hypochlorite (ClO - ), chlorite (ClO 2- ), chlorate (ClO 3- ), and perchlorate (ClO 4- ). Rule 2: Naming Simple Molecular Compounds. Molecular compounds are made up of molecules whose atoms are covalently bonded (shared electrons), usually nonmetals. A prefix (mono, di, tri, etc.), is used to indicate the number of atoms of each element in the molecule. For example in diphosphorus pentasulfide (P 2S 5,) the di- prefix in diphosphorus indicates there are two phosphorus atoms in the molecule. The prefix penta- in pentasulfide indicates there are five sulfur atoms in the molecule. The first part of the molecular compound name is the least electronegative atom. The prefix mono is usually not stated for the first element listed. For example, the substance CO is named carbon monoxide, NOT monocarbon monoxide. The second part of the molecular compound name is based on the element, with its ending dropped and ide added. A prefix is added to indicate the number of atoms (mono if only one atom.) Thus, CO 2 is named carbon dioxide, NOT carbon dioxygen and NOT carbon dioxygenide. Rule 3: Naming Acids and Bases. Acids and bases are formed when some ionic and covalent compounds, such as hydrogen chloride gas or sodium hydroxide solid, dissolve in water. In order to explain acid naming, the sequence of HCl, HClO, HClO 2, HClO 3, and HClO 4 are discussed in order. HCl is a binary acid. All binary acids are named the same way: The prefix "hydro" is used. The root of the anion is used. The suffix "ic" is used. The word "acid" is used as the second word in the name. The name for HCl is hydrochloric acid. HClO is an acid involving a polyatomic ion. Students must recognize the polyatomic ion in the formula. The STAAR Chemistry Reference Materials provides a list of common polyatomic ions. The polyatomic ion is ClO and its name is hypochlorite. Any time you see the "ite" suffix, you change it to "ous" and add the word acid. The name of HClO is hypochlorous acid. HClO 2 has the ClO 2 polyatomic ion in it. The name of this ion is chlorite.

5 The "ite" gets changed to "ous". The name of HClO 2 is chlorous acid. HClO 3 has the ClO 3 polyatomic ion and its name is chlorate. The "ate" gets changed to "ic". The name of HClO 3 is chloric acid. HClO 4 has the ClO 4 polyatomic ion and its name is perchlorate. The "ate" gets changed to "ic". The name of HClO 4 is perchloric acid. Bases are named similarly to naming ionic compounds with hydroxide (OH - ) as the anion. For example, NaOH is named sodium hydroxide. STAAR Note: Writing formulas for and naming compounds will be tested as Readiness Standards under Reporting Category 3: Bonding and Chemical Reactions. The STAAR Chemistry Reference Materials include a list of the common polyatomic ions, with names, formulas, and charges. GETTING READY FOR INSTRUCTION SUPPLEMENTAL PLANNING DOCUMENT Instructors are encouraged to supplement and substitute resources, materials, and activities to differentiate instruction to address the needs of learners. The Exemplar Lessons are one approach to teaching and reaching the Performance Indicators and Specificity in the Instructional Focus Document for this unit. Instructors are encouraged to create original lessons using the Content Creator in the Tools Tab located at the top of the page. All originally authored lessons can be saved in the My CSCOPE Tab within the My Content area. INSTRUCTIONAL PROCEDURES ENGAGE I Household Substances: What Compounds Do They Contain? 1. Place the common compounds around the room (see Advance Preparation). 2. Distribute a copy of the Handout: Common Compounds to each student. 3. Instruct students to work with a partner to fill in the table with common name, chemical formula, and formula name for as many of the compounds as they can. (Walk among students, and watch for prior knowledge of and possible gaps in students use of the rules for naming compounds and writing formulas). 4. Once students have attempted to complete the table, instruct partners to go to the areas where the boxes and bottles are located. Students should read the label information to discover any information they may be missing on their handout. NOTE: 1 Day = 50 minutes Suggested Day 1 empty containers of various simp common household substances (see Advance Preparation, 1 of each per teacher) glue or tape (per group) Attachments: Handout: Common Compounds per student) Teacher Resource: Common Compounds KEY 5. Only allow four students at a time per area, and limit the amount of time to allow for discussion. 6. Facilitate a discussion of the Common Compounds activity using the following questions. Accept all reasonalble answers at this time. Ask: Safety Note: Provide MSDS alongside the commo substances around the room. Instructional Note: Whenever possible, relate process

6 How well were you able to fill in the chart on your first attempt? What were the areas of difficulty for you? Which compounds were easily filled in; why? Did having the ingredients on the packages help you to write formulas for the compounds? What other information did you use? What information do you remember from previous science classes regarding naming compounds or writing formulas? 7. Explain that this unit will explore the chemist s rules for naming substances and writing chemical formulas. Accept all reasonable answers at this time. Ask: Is it important for us to be able to recognize chemical compounds from a formula; why or why not? Why would scientists need a common system to name compounds or write chemical formulas? Why would a common naming and formula writing system be of importance for MSDS sheets and safety concerns? 8. Instruct students to label their Common Substances table as a draft and affix the table into their science notebooks. Remind them they will need to update, and possibly correct, their table throughout the upcoming unit. 9. Introduce students to the organization known as IUPAC, and briefly describe their work in creating a common system of rules for naming chemicals and formulas. (Do not discuss the specific rules at this time.) 10. Instruct students to write a reflection in their science notebooks on reasons scientists need a system for naming chemical compounds and writing chemical formulas. skills, such as the use of MSDS shee to specific content being addressed within the lessons. STAAR Notes: Students differentiate between eleme and compounds in Grade 6 (6.5C). Students recognize that chemical formulas are used to identify substan and determine the type and number o atoms of each element in a substanc Grade 8 (8.5D). Science Notebooks: Students need to affix the draft of th Handout: Common Substances in t science notebooks. Additionally, students should write a reflection on the need for a common system for naming chemical compou and writing chemical formulas. EXPLORE/EXPLAIN I Oxidation Numbers Suggested Day 2 1. Distribute a copy of the Handout: Blank Periodic Table to each student. 2. Ask students to recall electron configurations, Lewis dot structures, and valence electrons from the previous unit by revisiting the manipulatives used during that lesson. 3. Given the information and manipulatives provided, ask students to look for a pattern between electron configurations, Lewis dot structures, and valence electrons. 4. Provide the oxidation numbers of the groups 1A 7A elements. (Refer to the STAAR Chemistry Reference Materials Periodic Table of the Elements.) Instruct students to label the group oxidation numbers on the Handout: Blank Periodic Table. colored pencils or markers (per group) glue or tape (per group) Attachments: Handout: Blank Periodic Table per student) Instructional Note: While the terms oxidation state and oxidation number are used interchangeably, oxidation number w be used in this lesson. Be sure to poi out that 4A can also be 4+.

7 5. Discuss how electron configurations can be used to predict oxidation numbers. Be sure that students see the relationship between valence electrons and oxidation numbers. 6. Instruct students to color their periodic Blank Periodic Table based on oxidation numbers. Have them make a key for their colors. 7. Facilitate a discussion in which students reflect upon any patterns of oxidation numbers they observe. 8. Remind students that the transition elements often have more than one oxidation number. Review as necessary. 9. Instruct students to color and label the transition elements on their Blank Periodic Table. Instruct them to add this information to their key. If you did not provide students with a copy of the STAAR Chemistry Reference Materials during the first u of the year, there is one available for download from the following website: sment/staar/science/ Science Notebooks: Students should glue their color-code Periodic Table with oxdation numbe in their science notebooks. 10. Instruct students to affix their new periodic tables into their science notebooks for reference. 11. Instruct students to write as many statements as they can in their science notebooks relating the electron configurations, Lewis dot structures, and valence electrons to the groups oxidation numbers based on their observations. EXPLORE/EXPLAIN II Formulas and Names for Ionic Substances Suggested Days 3, 4, and 5 1. Distribute a copy of pages 1 2 of the Teacher Resource: Ion Cards to each student. Instruct students to cut out the cards and lay them on their desks. Note: Using the Ion Cards, you will be repeating the same modeling and activity process for naming monatomic (pages 1 2), transition monatomic (page 3), and polyatomic (page 4) ionic compounds over a three day period. markers (per teacher) scissors (1 per student) glue or tape (per group) resealable plastic bags (1 per student) 2. Facilitate a brief discussion reviewing students on the concepts regarding ions. Ask: What is an ion? An atom or a group of atoms that has gained or lost one or more electrons and has become electrically charged What are positive ions are called? (Cations) What the negative ions are called? (Anions) 3. Instruct students to put the cations on the left side of their desks (facing the student) and the anions on the right side of their desks. Say: Follow me as I manipulate these cards, and make the same combinations as I do. Attachments: Teacher Resource: Ion Cards (s Advance Preparation, 1 per stud and 1 set for projection) Handout: Naming Compounds Practice Problems (1 per stude Teacher Resource: Naming Compounds Practice Problems KEY Instructional Notes: If you want to make cards on cardsto and laminate them, it will save the tim cutting out the cards. However, it will

8 4. Hold up one of the sodium ions, and put it on the Teacher Resource on an overhead projector or on a piece of paper on a document projector. Ask: What element is represented? (Sodium) Write sodium under the ion. 5. Hold up one of the chlorine ions, and put it on the Teacher Resource to the right of the sodium ion. Ask: What element is represented? (Chlorine) Write chlorine under the ion. 6. Bring the two ions together so that the plus sign and the minus sign both meet in the middle. Ask: What process have I just modeled? (How each ion s charge cancels the other out) Write NaCl under the compound. 7. Explain the IUPAC rules for naming the compound regarding the order of cation/anion and about changing the ending to -ide. Write the name sodium chloride under NaCl. Instruct students to find the location of sodium and chlorine on their periodic tables and then record the formula and the name for this compound in their student notebooks. 8. Continue this modeling process with several other combinations of ions, making sure the students understand how to write subscripts in the formulas. 9. Ask: How are elements combined to make chemical compounds? Accept reasonable answers related to definite proportions. 10. Review and discuss the law of definite proportions (also known as the law of constant composition and Proust s law). You might want to do an Internet search for additional background. 11. Compare and contrast hypotheses, theories, and laws such as these. allow students to keep cards to use in additional activities or for review. Model the process each day for three days. At the end of each day, give practice problems to students to reinforce the topic from that day. Be sure to review practice problems at th beginning of the following day to ens student understanding. If the students can handle dual concepts, you may want to bring oxidation numbers into your discussio as well. You may need to reinforce th use of Roman numerals with multival ions. You may want to create a separate Practice Problem set for writing the formulas. Present this to students wh instructionally appropriate. Be sure th students have been taught how to wr formulas before they are asked to do on a worksheet. STAAR Note: The STAAR Chemistry Reference Materials include a list of the commo polyatomic ions with names, formulas and charges. Science Notebooks: Students write examples of the formu and names of substances in their science notebooks. 12. Probe students thinking about what types of atoms will react to form compounds with other atoms. Refer back to the previous periodic table, if needed. Make sure students understand that not all atoms will react to form compounds with all other atoms. 13. Ask students to continue combining cards and writing formulas/names in their notebooks to see how many different combinations they can make. (Monitor for student understanding. You may want students to partner for this activity.)

9 14. Distribute a resealable, plastic bag to each student. Instruct students to store their cards in resealable, plastic bags for the following day. The resealable, plastic bags or envelopes of cards can be affixed in their science notebooks. 15. Distribute the Handout: Naming Compounds Practice Problems to each student. Assign the students monatomic ion practice problems. 16. Distribute to each student a copy of page 3 of the Handout: Ion Cards. 17. Instruct them to cut out the cards and add them to the card set of monatomic ions. 18. Ask: What do you notice about the transition monatomic ion cards? (They have two different charges/oxidation numbers.) 19. Repeat the modeling activity using two different iron (Fe) cards to model the formation of two different ionic substances. Explain to the students how to use Roman numerals to name ionic compounds formed by an element that have more than one charge/oxidation number. 20. Ask students to continue combining cards and writing formulas/names in their notebooks to see how many different combinations they can make. Monitor for student understanding. You may want students to partner for this activity. 21. Have students store their cards in resealable, plastic bags for the following day. 22. Assign the students transition monatomic practice problems from the Handout: Naming Compounds Practice Problems. 23. Distribute to each student a copy of page 4 the Handout: Ion Cards. 24. Instruct them to cut out the cards and add them to their growing set of ion cards. 25. Ask: What do you notice about the polyatomic ion cards? They have positive and negative charges. Some contain oxygen. Some do not have oxygen. 26. Repeat the modeling activity for polyatomic ions. Use two examples to illustrate how polyatomic ions are written into formulas using parentheses. Give students the names for any additional polyatomic ions they will need

10 for the following activity. 27. Ask students to continue combining cards and writing formulas/names in their notebooks to see how many different combinations they can make. Monitor for student understanding. You may want students to partner for this activity. 28. Instruct students to store their cards in resealable, plastic bags and affix the bags in their student notebooks. These may be used for additional activities or for review. 29. Assign the students polyatomic practice problems Handout: Naming Compounds Practice Problems. ELABORATE I Formulas for Ionic Compounds Suggested Days 6 and 7 1. Distribute to each student a copy of the Handout: Writing and Naming Ionic Compounds. 2. Guide students through the process of how to fill in the table with the chemical formula and name of the compound. Students may need assistance with NO 3-1 because nitrate was not a polyatomic ion used in the previous activity. 3. Allow students a short amount of time to work on this process, and then use the Teacher Resource: Writing and Naming Ionic Compounds KEY to check together for student understanding. 4. Explain to students they will work in groups to conduct an investigation to form some insoluble ionic substances. They will write the formula and name for each compound they observe. 5. Divide students into groups. Note: You will need to decide on group size so you can manage the five stations. 6. Project the Teacher Resource: Formulas for Ionic Compounds Sample Data Table. Instruct students to prepare a similar data table in their science notebooks. 7. Review the procedure from the Teacher Resource: Formulas for Ionic Compounds Station Cards. Show students a spot plate or a glass plate with a piece of black paper under one side of it and a piece of white paper under the other side. 8. Explain to students that they will be putting a drop of two different substances together on the spot plate or glass plate that will result in the formation of an insoluble ionic compound. This is called a precipitate. 9. Demonstrate the procedure. If using a glass plate, point out the advantage of placing the drops so they are partially on the black area and partially on safety goggles (1 per student) glass or spot plates (1 per station black and white paper (if using glass plates, 1 sheet of each colo per station) solutions (see Advance Preparat in 24 dropper bottles or small disposable cups). Label each ONLY with the ION in parenthese as follows: 1 silver nitrate (Ag +1 ) 1 lead (II) nitrate (Pb +2 ) 1 copper (II) sulfate (Cu +2 ) 1 magnesium sulfate (Mg +2 ) 1 iron (III) chloride (Fe +3 ) 2 iron (III) chloride (Cl -1 ) 2 potassium iodide (I -1 ) 5 sodium hydroxide (OH -1 ) 5 sodium carbonate (CO 3-2 ) 5 sodium phosphate (PO 4-3 ) eyedroppers or disposable pipett if using cups Attachments: Handout: Writing and Naming Ionic Compounds (1 per studen Teacher Resource: Writing and

11 Instead of spot plates or glass plates other reacting surfaces, such as plas sleeves, plastic wrap, or overhead film could be used. Chemistry the white area of the glass plate, in order to see the color of the precipitates more easily. 10. Instruct students in the proper way to clean up the spot or glass plate when they finish at each station. Review safety precautions (see Safety Notes). 11. Instruct student teams to move from station to station at your signal until they have completed all five stations in the investigation. Point out that some stations have more tests than others. 12. Monitor students as they conduct the investigation, checking for correct procedure and assisting students in writing correct formulas and names. 13. After the investigation is complete, ask each group to meet with another group to compare and discuss their results. You can also post results on a transparency to have groups verify results and discuss findings. 14. Conduct a discussion to clarify any areas of disagreement or confusion. Use the Teacher Resource: Formulas for Ionic Compounds Sample Data Table KEY as a guide. 15. Allow students to correct their data tables to reflect the correct formulas and names. Naming Ionic Compounds KEY copy to project or an overhead Teacher Resource) Teacher Resource: Formulas fo Ionic Compounds Station Ca (1 per station) Teacher Resource: Formulas fo Ionic Compounds Sample D Table (1 for projection) Teacher Resource: Formulas fo Ionic Compounds Sample D Table KEY Teacher Resource: Formulas fo Ionic Compounds Teacher Instructions and KEY Safety Notes: Wear safety goggles throughout the l MSDS for all substances used should be available and reviewed by studen Instructional Notes: NOTE: Distribute the labeled dropper bottles or cups and other materials a the appropriate stations following the Teacher Resource. Science Notebooks: Students prepare a data table in their science notebooks. They record observations and write in symbols for cations, anions, formulas, and names for the ionic compounds. EXPLORE/EXPLAIN IV Formulas and Names for Molecular (Covalent) Substances 1. Read to students several of the dangers of dihydrogen monoxide to students (see Advance Preparation). 2. Ask: Suggested Day 8 glue or tape (per group)

12 Raise your hand if you think you know the common name of DHMO, dihydrogen monoxide? Accept all reasonable answers at this time. Some students might get the idea and know that you are talking about water. However, don t confirm their suspicions at this time. Inform them you will come back to DHMO later in the lesson. 3. Ask students to brainstorm the prefixes for the numbers from one to ten with a partner. Instruct students to jot down the prefixes they remember. 4. Call for volunteers to call out the prefixes they remembered and record them on the board. Fill in any prefixes the students may not remember. 5. Write the names and formulas for the following molecular (covalent) substances on the board: CO, carbon monoxide (not mono-oxide) CO 2, carbon dioxide N 2O, dinitrogen monoxide 6. Ask students what pattern they observe in the naming system. 7. Write the formulas for water and hydrogen peroxide on the board, and ask students to name them using prefixes. At this point, students may make the connection that DHMO is water, if they haven t already. If not, guide them through the process to determine that DHMO is water and the purpose of the DHMO hoax. Attachments: Handout: Prefixes for Binary Molecular Compounds (see Advance Preparation, 1 card per student) Instructional Note: The purpose of today s opening activ is to introduce the naming of covalen substances. Use the diatomic elements (H 2,N 2,O 2 Cl 2, Br 2, I 2) to reinforce covalent bonding. You may need to provide examples o naming when the element name beg with a vowel: mon-oxide, but tri-iodid 8. Write the formulas of a few additional substances and ask students to predict what the names would be based upon the prefixes they brainstormed earlier. 9. Review the diatomic elements (H 2,N 2,O 2, F 2, Cl 2, Br 2, I 2) and where they are located in the periodic table. 10. Provide each student a copy of the table provided on the Handout: Prefixes for Binary Molecular Compounds. Instruct students to affix the handout to their science notebooks. 11. Close the lesson by discussing why it is important that people understand how chemical compounds are named. Encourage students to look at the ingredients on common kitchen and cleaning items at home to see how these names are being used. EXPLORE/EXPLAIN V Naming Acids and Bases Suggested Day 9 1. Display several dilute acids and bases. Ask: What is an acid? Accept all reasonable answers. Can you give an example of an acid? Accept all reasonable answers. several dilute acids (hydrochloric nitric, nitrous, acetic, and/or sulfu several types per teacher, 1 labe

13 2. Demonstrate and explain that an acid is a substance that turns blue litmus red, has a ph of less than seven, and contains hydrogen ions (see Instructional Notes). Review safety precautions for handling acids with students (see Safety Notes). Use both litmus paper and a ph probe to show results. 3. Point to examples and write the names of the acids you are showing on the board. Include the names of accurate examples that students volunteered. It may help use a visual display, such as a T-chart or ph scale on the board, to clarify the results of the testing demonstration. 4. Present the rules for naming acids from the IUPAC guidelines. Show students the process of naming several acids with different numbers of oxygen atoms. 5. Instruct students to write a description of acids and names and formulas for acids in their science notebooks. If you used a T-chart on the board, instruct students to use the T-chart in their notebooks. 6. Ask: What is a base? Accept all answers. Can you give an example of a base? Accept all answers. 7. Demonstrate and explain that a base is a substance that turns red litmus blue, has a ph of greater than seven, and contains the hydroxide ion (OH). Point to examples, and write the names of the bases you are showing on the board. Include the names of accurate examples that students volunteered. Complete the visual display (T-chart or ph scale) on the board, showing the variation of the acids from the bases. 8. Present the rules for naming bases from the IUPAC guidelines. Show students the process of naming several bases. 9. Instruct students to write a description of bases and names and formulas for bases in their science notebooks. reagent bottle of each type) several dilute bases (sodium hydroxide, calcium hydroxide, and/or ammonium hydroxide, several types per teacher, 1 labe reagent bottle of each type) litmus paper (per teacher) 100 ml beakers to hold samples acids and bases for testing ph meter or ph probe (per teach goggles (1 per teacher) Safety Notes: Demonstrate safety when handling acids and bases by wearing goggles. Demonstrate proper disposal after testing. MSDS for all substances used should be available and reviewed by the students. Instructional Note: More formal definitions of acids and bases will be provided in Unit 11: Ac and Bases. Science Notebooks: Students write general descriptions o acids and bases and then names and formulas for each in their science notebooks. ELABORATE II Another Look at Household Substances Suggested Day Place empty containers of more complex household products on lab tables (See the Advance Preparation section and Safety Notes.). 2. Inform students that they will be working in groups to look through the ingredients in products and write down any compounds that are listed in the ingredients. 3. Divide students into groups of 2 3. Monitor students as they rotate through the tables of products until they get back to the place where they started. empty containers of various more complex common household substances (see Advance Preparation, 1 each per teacher) Safety Notes:

14 4. Once groups return to the table where they started, facilitate a group level discussion in which students reflect on their findings. Ask groups to discuss the following: What ionic compounds did you identify? Molecular compounds? Acids? Bases? How were you able to tell what the compounds were? 5. Ask groups to share with the class some of the types of compounds they found and their rationale for determining what the compounds are. 6. Instruct students to work in their groups to name and write the formulas for the products. Note: Students may need additional resources to write the formulas. Make sure containers are empty and cleaned of any potentially hazardous compounds. Provide MSDS alongside the commo substances around the room. Science Notebooks: Students should write the names and formulas of substances from the prod labels in their science notebooks. 7. Monitor and assist the students as they work to complete the process. 8. When students are finished, ask for groups to share out loud with the class. Explain that more complex substances, including organic molecules, are named using additional or differing IUPAC rules. Relate some of the biomolecules, such as carbohydrates, proteins, and lipids, to students knowledge of biology. Explain to students that even though we have IUPAC rules to name compounds, even scientists use commonly accepted names such as water in their work. EVALUATE Performance Indicator Suggested Days 11 and 12 Performance Indicator Given a set of 3 5 elements, write the names and formulas of several ways that the elements might combine to make compounds and/or polyatomic ions. Select two compounds to explain, orally and in writing, how and why the compound can be made from a given set of elements. (C2.F, C2.I; C.7A, C7.B) 5B, 5F 1. Refer to the Handout: Element Cards PI (1 per student) and Teacher Resource: Performance Indicator Instructions KEY for information on administering the assessment. blank transparencies (3 4 per teacher) markers for transparencies (3 4 teacher) paper towels (3 4 per class) Attachment: Handout: Element Cards PI (1 p student) Teacher Resource: Performance Indicator Instructions KEY