INTRODUCTION: Every academic discipline or field of study has its own specific vocabulary and its own set of technical words. Chemistry is no different. As we learn Chemistry this year you will learn many new words, which have specific meaning to the chemist. An important group of words, which you will learn in this unit, are the chemical names for various compounds. These names contain a significant amount of information about the compounds, specifically the whole number ratio of types of atoms, which make up the compound. There are two basic types of compounds, ionic and covalent. The elements in these compounds are bound together. There are two so-called types of bonding, ionic and covalent. Actually these types are two extremes on a continuum of degree of interaction between the electrons of one atom and the nucleus of the other atom to which it is bonded. Bonding between atoms occurs by the balance of the attractive forces between the positive nuclei of atoms and the electron clouds of other atoms. When the attraction of one atom’s nucleus for electrons of another atom is so strong that electrons are, in essence, transferred between them, a bond forms between the two oppositely charged ions; hence this bond is called “ionic.” When the two bonding atoms have an equal or close to equal attraction for the bonding electrons, covalent bonding takes place. In this unit we will learn how to name examine both ionic and covalent bonding, as well as properties of each of these types.
OBJECTIVES: As you study this unit, you should be able to do the following:
1. Describe the formation of a cation from an atom of a metallic element and of an anion from a nonmetallic element, using the octet rule and the importance of noble-gas electron configurations. (7.1)
2. Give the name of various cations and anions. (7.1)
3. Describe the formation of an ionic bond, and then an ionic compound. (7.2)
4. State the basic properties of ionic compounds. (7.2)
5. Write the chemical formulas for binary and ternary ionic compounds from the name and write the name given the formula. (9.2)
6. State a few basic properties of molecular compounds. (8.1)
7. Differentiate between an ionic compound and a molecular compound based on the name or the formula. (8.1)
8. Describe how electrons are shared to give an octet in the formation of single, double and triple covalent bonds. (8.2)
9. Create Lewis electron dot diagrams for covalent molecules containing single, multiple and resonance bonds. (8.2 and GIAs)
10. Describe the shapes of simple covalent molecules using VSEPR theory. (8.3 pp. 232-233)
11. Categorize a bond as non-polar covalent, polar covalent, or ionic using electronegativity values, and show the relationship between polar covalent bonds and polar molecules. (8.4)
12. Draw atomic level pictures that represent states, types and formulas of compounds. (GIAs)
13. Write the chemical formulas for binary molecular compounds from the name and write the name given the formula. (9.3)
LEARNING ACTIVITIES:
To learn about objectives 1-5 (Ionic Compounds):
READ Chapter 7, Sections 1 & 2; pp. 186-199.
MEMORIZE names and formulae of polyatomic ions found in Table 9.3 on page 257.
READ Section 9.2, pp. 260-266.
EXAMINE the flowchart for naming compounds, included in this unit packet and on p. 277.
WRITE "GIA4-1: Writing Names and Formulas for Chemical Compounds"
PRACTICE naming and writing formulas with Naming Exercise Practice Sheet - Ionic Compounds then Check Your Answers.
TAKE the Practice Quiz on Ionic Compounds then Check Your Answers.
WRITE answers to Chapter Assessment questions in Ch. 7 on p. 207: 31, 32, 36, 37, 38, 41, 45, 47 and in Chapter 9 on pp. 281-282:49, 51, 52, 53, 66.
For objectives 6-15 complete the following activities (Lewis Structures and molecular structure):
READ Chapter 8, pp. 212-229 and 232-233. (Exclude sections on molecular orbitals and hybrid orbitals.)
PRACTICE building models using lab activity worksheet, “Building Molecular Models" using lab activity worksheet.
WRITE answers to Chapter 8 Assessment questions on pp. 247-248: 39, 42-44, 46, 49, 50, 54, 58, 63-65.
PRACTICE using the Naming Exercise Practice Sheet; Check Answers to Exercise
MORE PRACTICE on Names and Formulas. Check your answers to this exercise.
WRITE answers to Chapter Assessment questions in Chapter 9 on pp. 281-282: 57, 58, 60, 65, 68-70.
To make sure you understand the objectives for this unit:
ASK me, the teacher, any lingering QUESTIONS
TAKE the Unit’s Self-Test and the “Standardized Test Prep” questions at the ends of chapters 7-9 on pages 211, 251, 285. CHECK YOUR ANSWERS.
PROPOSED DUE DATES:
Quiz Monday, Nov. 12, Objectives 1-5, Ionic Compounds (Chapter 7 and 9.2) (Ch. 7 homework due same day)
Unit 4 TEST DATE: Tuesday, November 20, 2007 The following homework is due same day: Chapter 8 Assessment questions assigned above on p. 247 and Chapter 9 Assessment questions on pp. 281-282: 57, 65, 68-70.
