Naming Compounds and Chemical Formulas

Transcription

1 Naming Compounds and Chemical Formulas A task from Formative Assessment Activities for High School Chemistry In this activity, students will demonstrate their ability to name compounds and write chemical formulas, including ionic and covalent compounds, acids, bases, and polyatomic ions, according to IUPAC nomenclature rules. This manipulative activity will reinforce an understanding of electron interactions as elements, including main group elements and transition metals, interact to form stable compounds. Teachers will be able to formatively assess students ability to correctly name compounds and their understanding of the interactions that lead to the formation of compounds. This task supports these student expectations from the Texas Essential Knowledge and Skills for Science 1 : (7) Science concepts. The student knows how atoms form ionic, metallic, and covalent bonds. The student is expected to: (A) 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; (B) write the chemical formulas of common polyatomic ions, ionic compounds containing main group or transition metals, covalent compounds, acids, and bases; (2) Scientific processes. The student uses scientific methods to solve investigative questions. The student is expected to: (I) communicate valid conclusions supported by the data through methods such as lab reports, labeled drawings, graphs, journals, summaries, oral reports, and technology-based reports 1 Text with a line through it indicates this part of the TEKS is not being addressed in this activity. A resource from The Charles A. Dana Center at The University of Texas at Austin

2 Formative Assessment Activities for High School Chemistry Bonding and Chemical Reactions Naming Compounds and Chemical Formulas Purpose The purpose of this station is to reinforce students ability to name compounds and write chemical formulas, and to compare interactions between ions and interactions between atoms to form molecules. Teacher Pages 119

3 Formative Assessment Activities for High School Chemistry Bonding and Chemical Reactions Naming Compounds and Chemical Formulas Teacher Pages Essential Understandings Materials Use prefixes to name covalent compounds. For ionic compounds, name the metal or cation first, then name the nonmetal or anion, changing the end of the names of single element anions to ide. The name of an acid depends on the type of anion it has. Ionic chemical formulas are based on neutral compounds formed from the attraction of positive and negative ions. Covalent compounds are formed when nonmetals share valence electrons in order to complete their outer energy level. Magnetic tape (1 half-inch wide roll per station) Metal baking sheet (1 per station) In addition to the blackline masters, the following materials are needed to make the Covalent Compound Cards: 90 black beads or half-beads (approximately 6 mm in diameter) with adhesive backs Acrylic glue (SuperGlue ) or hot glue (if beads are not self-adhering) Scissors Hole punch The following materials are included in the blackline masters for this station. Station Information Sheet (1 per station) Periodic Table of the Elements (1 per station) How Compounds Are Named Flowchart (1 per station) Covalent Compound Cards (1 set per station) Anion and Cation Cards (1 set per station) Student Pages (1 set per student) 120 Teacher Pages

4 Formative Assessment Activities for High School Chemistry Advance Preparation 1. Print one copy of all the blackline masters for this station using a color printer. Color is essential to the station activities. Make one copy of the Student Pages (including the glossary) for each student. 2. Laminate the Station Information Sheet, the Periodic Table of the Elements, and the How Compounds Are Named Flowchart. 3. Laminate and cut apart the Covalent Compound Cards. Use a hole punch to make holes where there are white dots in the cards. Glue or stick the 90 beads or half beads to the black dots to represent electrons. After the cards are laminated, use a pair of sharp scissors to cut along the dotted line on each of the cards stopping just before reaching the letter on the card. The cards are assembled by sliding them together until the holes and beads match up. In the example on the right, the holes and the beads on the hydrogen cards line up with the holes and beads on the silicon card. Lock the four hydrogen cards to the silicon card to complete this example model. Teacher Pages 121

5 Formative Assessment Activities for High School Chemistry 4. Laminate and cut apart the Anion and Cation Cards. Place a piece of magnetic tape on the back of each card. Place the cards in an envelope and label it. Station Setup 1. Tape the Station Information Sheet to the station table. Students will use this to confirm the station is set up correctly. 2. Place the How Compounds Are Named Flowchart, the Covalent Compound Cards, the Anion and Cation Cards, and the metal baking sheet at the table. Procedures 1. Tell students to check the station setup against the Station Information Sheet when they arrive at the table. If anything is missing or out of place, they should notify you. 2. Pass out a copy of the Student Pages to each student. Instruct students to work through the procedures and answer the questions with their teammate(s). 3. As students work through the station activity, circulate around the room, checking their work and responding to questions. Guide to Student Responses Note The suggested student responses presented below in italics represent the best possible answers to the student questions; actual student responses may vary. Essential Question What features of compounds and chemical formulas do scientists use to determine the names for the compounds and formulas? Scientists use the compound or formula s type of bonding (ionic or covalent), its location on the periodic table, and whether it is a main group or transition metal to name compounds and chemical formulas. 122 Teacher Pages

6 Formative Assessment Activities for High School Chemistry 1. Locate the How Compounds Are Named Flowchart and use it to name the compounds in the table below. Compound ClO 2 HCl (aq) NH 4NO 3 Pb(NO 3) 2 Fe 2O 3 H 2CO 3 C 2Br 6 HNO 3(aq) HCl (g) KOH (aq) Name Chlorine dioxide Hydrochloric acid Ammonium nitrate Lead (II) nitrate Iron (III) Oxide Carbonic acid Dicarbon hexabromide Nitric acid Hydrogen chloride Potassium hydroxide Part II: Chemical Formulas 2. Continue using the How Compounds Are Named Flowchart to complete the table by writing the chemical formulas for the following covalent compounds. Example: Tetrasulfur dinitride S 4N 2 Covalent Compound Name Covalent Compound Formula Dinitrogen trioxide N 2O 3 Carbon tetrachloride CCl 4 Disulfur trifluoride S 2F 3 Teacher Pages 123

7 Formative Assessment Activities for High School Chemistry 3. Use the Covalent Compound Cards to determine the chemical formulas for the following compounds: a. A compound with carbon and fluorine: CF 4 b. A compound with silicon and hydrogen: SiH 4 c. A compound with sulfur and bromine: SBr 2 4. Locate the Anion and Cation Cards. Match the cards and arrange them on the baking sheet so that they represent the neutral compounds listed in the table. Complete the table by giving the correct chemical formulas for the compounds. Ionic Compound Name Ionic Compound Formula Copper (I) sulfate Cu 2SO 4 Calcium carbonate CaCO 3 Copper (II) nitrite Cu(NO 2) 2 Iron (III) oxide Fe 2O 3 Ammonium phosphate (NH4) 3PO Teacher Pages

8 Formative Assessment Activities for High School Chemistry 5. What are three other ionic compounds you can make using these cards? May include, but not limited to: PbI 2, MgCl 2, Be(OH) 2, Cu(NO 2) 2, Fe(OH) 3, NH 4I, NH 4OH 6. Now that you have completed these exercises, return to the Essential Question. Would you like to modify or change your answer? Write any modifications to your answer below. Answers will vary. Teacher Pages 125

9 Formative Assessment Activities for High School Chemistry 126 Teacher Pages

10 Formative Assessment Activities for High School Chemistry Blackline Masters for Bonding and Chemical Reactions Naming Compounds and Chemical Formulas Contents Station Information Sheet How Compounds Are Named Flowchart Covalent Compound Cards Anion and Cation Cards Periodic Table of the Elements 127 Blackline Masters

11 Formative Assessment Activities for High School Chemistry Station Information Sheet IONIC COMPOUNDS Two elements metal + nonmetal Name the metal first, then the nonmetal. Change the ending of the nonmental to -ide. Example: NaCl (Sodium chloride) If the metal is a that can have more than one charge, use Roman numerals to show the charge. Example: Fe 2 O 3 (Iron (III) oxide) More than two elements: or metal first, then the anion or nonmetal, using the -ide ending for single nonmetal anions. Example: NH 4 Cl (Ammonium chloride) How Compounds are Named Acetate C 2 H 3 O 2, CH 3 COO Ammonium NH 4 + Carbonate CO 3 2 Chlorate ClO 3 Chlorite ClO 2 Chromate CrO 4 2 Cyanide CN Dichromate Cr 2 O 7 2 Hydrogen Carbonate HCO 3 H + nonmetal Use the prefix hydro and change the ending of the name of the nonmetal to ic. Example: HCl (Hydrochloric acid) Polyatomic Ions ACIDS H + oxy-anion Change the ending of oxy-anion: -ate to -ic -ite to -ous Examples: H 2 SO 4 (Sulfuric acid) H 2 SO 3 (Sulfurous acid) Hydroxide OH Hypochlorite ClO Nitrate NO 3 Nitrite NO 2 Perchlorate ClO 4 Permanganate MnO 4 Phosphate PO 4 3 Sulfate SO 4 2 Sulfite SO 3 2 COVALENT COMPOUNDS Nonmetal + nonmetal Use prefixes to indicate how many atoms of each element are in the compound. Change the ending of the second element to -ide. Example: N 2 O 4 (Dinitrogen tetroxide) Mono- Di- Tri- Tetra- Penta- Hexa- Hepta- Octa- Nona- Deca- Prefixes one two three four five six seven eight nine ten Note: Mono- is rarely used. Also, when two vowels come together, drop the second vowel. Oxide O 2 Nitrite NO2 Nitrite NO2 Si Covalent Compound Cards w Oxide O 2 + Cu 2+ Copper + Anion and Cation Cards Baking Sheet 128 Blackline Masters

12 Formative Assessment Activities for High School Chemistry How Compounds Are Named Flowchart COVALENT COMPOUNDS Nonmetal + nonmetal Use prefixes to indicate how many atoms of each element are in the compound. Change the ending of the second element to -ide. Example: N 2 O 4 (Dinitrogen tetroxide) Mono- Di- Tri- Tetra- Penta- Hexa- Hepta- Octa- Nona- Deca- Prefixes one two three four five six seven eight nine ten Note: Mono- is rarely used. Also, when two vowels come together, drop the second vowel. IONIC COMPOUNDS ACIDS Two elements metal + nonmetal Name the metal first, then the nonmetal. Change the ending of the nonmental to -ide. Example: NaCl (Sodium chloride) If the metal is a transition metal that can have more than one charge, use Roman numerals to show the charge. Example: Fe 2 O 3 (Iron (III) oxide) More than two elements: cation + anion Name the cation or metal first, then the anion or nonmetal, using the -ide ending for single nonmetal anions. Example: NH 4 Cl (Ammonium chloride) Acetate C 2 H 3 O 2, CH 3 COO + Ammonium NH 4 2 Carbonate CO 3 Chlorate ClO 3 Chlorite ClO 2 2 Chromate CrO 4 Cyanide CN 2 Dichromate Cr 2 O 7 Hydrogen Carbonate HCO 3 H + nonmetal Use the prefix hydro and change the ending of the name of the nonmetal to ic. Example: HCl (Hydrochloric acid) Polyatomic Ions H + oxy-anion Change the ending of oxy-anion: -ate to -ic -ite to -ous Examples: H 2 SO 4 (Sulfuric acid) H 2 SO 3 (Sulfurous acid) Hydroxide OH Hypochlorite ClO Nitrate NO 3 Nitrite NO 2 Perchlorate ClO 4 Permanganate MnO 4 3 Phosphate PO 4 2 Sulfate SO 4 2 Sulfite SO 3 Charles A. Dana Center at The University of Texas at Austin Blackline Masters Blackline Masters

13 Covalent Compound Cards Formative Assessment Activities for High School Chemistry 130 Blackline Masters

14 Formative Assessment Activities for High School Chemistry Covalent Compound Cards 131 Blackline Masters

15 Covalent Compound Cards Formative Assessment Activities for High School Chemistry Si Si 132 Blackline Masters

16 Formative Assessment Activities for High School Chemistry Anion and Cation Cards Charles A. Dana Center at The University of Texas at Austin Blackline Masters Blackline Masters

17 Anion and Cation Cards Formative Assessment Activities for High School Chemistry 134 Blackline Masters

18 Formative Assessment Activities for High School Chemistry Anion and Cation Cards Oxide O 2 Oxide O 2 + Fe 3+ Iron (III) Fe 3+ Iron (III) Blackline Masters

19 Formative Assessment Activities for High School Chemistry 136 Blackline Masters

20 Formative Assessment Activities for High School Chemistry Bonding and Chemical Reactions Student Pages Purpose The purpose of this station is to reinforce your ability to name compounds and write chemical formulas, and to compare interactions between ions and interactions between atoms to form molecules. Before You Begin Check to see that all the items are present and organized according to the Station Information Sheet. If you notice a problem, notify your teacher immediately. Materials Station Information Sheet Periodic Table of the Elements How Compounds Are Named Flowchart Covalent Compound Cards Anion and Cation Cards Metal baking sheet Essential Question What features of compounds and chemical formulas do scientists use to determine names for compounds and formulas? Student Pages 137

21 Formative Assessment Activities for High School Chemistry Part I: Naming Compounds 1. Locate the How Compounds Are Named Flowchart and use it to name the compounds in the table below. Compound Name ClO 2 HCl (aq) NH 4 NO 3 Pb(NO 3 ) 2 Fe 2 O 3 H 2 CO 3(aq) C 2 Br 6 HNO 3(aq) HCl (g) KOH (aq) Part II: Chemical Formulas 2. Continue using the How Compounds Are Named Flowchart to complete the table by writing the chemical formulas for the following covalent compounds. Example: Tetrasulfur dinitride S 4 N 2 Covalent Compound Name Covalent Compound Formula Dinitrogen trioxide Carbon tetrachloride Disulfur trifluoride 138 Student Pages

22 Formative Assessment Activities for High School Chemistry 3. Use the Covalent Compound Cards to determine the chemical formulas for the following compounds: a. A compound with carbon and fluorine: b. A compound with silicon and hydrogen: c. A compound with sulfur and bromine: 4. Locate the Anion and Cation Cards. Match the cards and arrange them on the baking sheet so that they represent the neutral compounds listed in the table. Complete the table by giving the correct chemical formulas for the compounds. Example: Copper (I) phosphate Cu 3 PO 4 Ionic Compound Name Ionic Compound Formula Copper (I) sulfate Calcium carbonate Copper (II) nitrite Iron (III) oxide Ammonium phosphate 5. What are three other ionic compounds you can make using these cards? 6. Now that you have completed these exercises, return to the Essential Question. Would you like to modify or change your answer? Write any modifications to your answer below. NOTE: Because other students are going to do the activity after you, be sure to put all the materials at the station back as you found them. Sometimes there will be materials that need to be renewed or replaced. If you need assistance or have any questions, ask your teacher. Student Pages 139

23 Formative Assessment Activities for High School Chemistry I Need to Remember... Complete this part after class discussion of this station. I need to remember Student Pages

24 Formative Assessment Activities for High School Chemistry Glossary for Acids Acids are compounds that contain hydrogen (H + ) and that, when dissolved in water, increase the concentration of hydrogen ions. Anion An anion is an ion that has gained one or more electrons and that has a negative charge. Cation A cation is an ion that has lost one or more electrons and that has a positive charge. Compound A compound is a substance composed of two or more elements that are chemically combined. Covalent Bond Ion Covalent bonds are the chemical bonds that form when two atoms share one or more electron pairs. An ion is an atom or group of atoms that has gained or lost one or more electrons and thus has either a positive or negative charge. Ionic Bond Ionic bonds are the bonds that form when atoms link together due to the attraction of opposite charges. Student Pages 141