Chemistry HS/Science Unit: 05 Lesson: 01 Suggested Duration: 12 days Chemical Nomenclature 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 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 C.7B 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 Distinguish between scientific hypotheses and scientific theories. C.2E 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. C.2F Collect data and make measurements with accuracy and precision. C.2H Organize, analyze, evaluate, make inferences, and predict trends from data. C.2I 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. Ð 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. Ð Why is it important that there is a consistent way to name chemical compounds? Ð What information can be derived from the name of a compound? Vocabulary of Instruction: • ion • law of definite proportions • anion • chemical formula • cation • molecule • oxidation number • IUPAC (International Union of Pure and Applied Chemistry) • ionic compound • base Materials: ©2012, TESCCC 06/17/13 page 1 of 14 Chemistry HS/Science Unit: 05 Lesson: 01 Refer to Notes for Teacher 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) +2 • 1 lead (II) nitrate (Pb ) • 1 copper (II) sulfate (Cu+2) Chemistry HS/Science Unit: 05 Lesson: 01 • 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) -2 • 5 sodium carbonate (CO3 ) -3 • 5 sodium phosphate (PO4 ) 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). Chemistry HS/Science Unit: 05 Lesson: 01 • 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 (SO3 ) and sulfate (SO4 )). 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 (ClO2 ), chlorate (ClO3 ), and perchlorate (ClO4 ). 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 (P2S5,) 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, CO2 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, HClO2, HClO3, and HClO4 are discussed in order.