Chapter 7 Chemical Bonding

Transcription

1 Chapter 7 Chemical Bonding 1. Define electronegativity. 2. How is the strength of a bond between two elements in a molecule related to their electronegativities? 3. What is the difference between an ionic and a covalent bond? 4. How is the character of a bond (ionic or covalent) between two elements related to their electronegativities? 5. Referring to electronegativit.ies, in your text, arrange the following compounds in order of increasing ionic character of their bonds: LiBr, SO 2, Ca 3 P 2, LiF 7. Referring to Tables of electronegativities in your text, classify each of' the following bonds as either ionic: (I) or covalent (C) a. A1-O f. N-O b. Al-S g. Na-S c. Bi-CI h. P-O d. Bi-O i. S-O e. C- Cl j. Ti-Br 8. List four general characteristics of compounds that have ionic bonds 9. Bonds between the which of the following pairs are covalent or ionic? Al Cl N O K F S O H. Cannon, C. Clapper and T. Guillot Klein High School

2 Ba Cl Fe O 10. List three general characteristics of compounds formed entirely by covalent bonds. 11. List three characteristics of metals. 12. How does the bonding of atoms in a metal differ from the bonding in a nonmetal? 13. Indicate whether each property listed below is characteristic of ionic (I), covalent (C), or metallic (M) bonding More than one letter may be used for each answer. a. Shape of solid can be changed by pounding. b. Not electrically conducting in solid phase c. Electrically conducting in all phases d High melting points 7-2

3 Chapter 7 Bonding Worksheet 1) A chemical bond between atoms results from what? a. transfer of electrons b. sharing of electrons c. attraction of oppositely charged ions d. all of the above 3) As the electronegativity difference between two atoms bonded together increases, the percentage of what else increases? a. ionic character b. covalent character c. metallic character d. electron sharing 2) What makes up a covalent bond? a. a shared electron b. two different ions c. an octet of electrons d. a shared electron pair 4) Which of the following would describe the electronegativity of an atom with a strong attraction for the electrons they share with another atom? a. high electronegativity b. low electronegativity c. zero electronegativity d. Lewis electronegativity 7. What do we call the electrons involved in forming a chemical bond? 8. If a bond s character is more than 50% ionic, what type of bond is formed? 9. If a bond s character is more than 50% ionic, what can we say about the electronegativity difference between the two atoms? 10. What is an example of an molecular compound? 11. What type of bonding holds a polyatomic ion together? 12. What type of forces holds two atoms together in an ionic bond? Complete the following table Covalent Ionic Components Overall charge Conductivity Melting point Structure of compound Solubility in water

4 Covalent Compounds Name the following Compounds Write formulas for the following 1. ClO 2 2. sulfur dioxide 3. N 2 O 5 4. carbon dioxide 5. CCl 4 6. carbon monoxide 7. N 2 O 3 8. dinitrogen monoxide 9. PCl diphosphorus pentasulfide 11. P 4 O dinitrogen tetroxide 13. PCl tetraphosphorus decoxide 15. SF sulfur trioxide 17. CS dinitrogen pentoxide 19. SO trihydrogen nitride 21. sulfur hexafluoride 22. dinitrogen trioxide 23. disulfur dichloride 24. disulfur decafluoride 25. diboron tetrabromide 7-4

5 Write the formulas for the following: 1. sodium hydroxide 16. antimony (V) phosphide 2. lithium bromide 17. potassium phosphate 3. aluminum bicarbonate 18. plumbic perchlorate 4. ferrous oxide 19. stannous fluoride 5. dinitrogen pentoxide 20. nickel (III) phosphide 6. chromium (II) nitrate 21. carbon tetrachloride 7. chromium (VI) oxide 22. ammoniun sulfite 8. mercury (II)chloride 23. iron (III) oxalate 9. gold (III) oxide 24. arsenic trichloride 10. aluminum bicarbonate 25. carbon monoxide 11. cupric sulfide 26. calcium chloride 12. nickel (III) phosphide 27. cobalt (II) iodide 13. carbon tetrahydride 28. sulfur dioxide 14. aluminum carbide 29. ferric oxide 15. titanium (lli) phosphate 30. titanium (IV)phosphate 7-5

6 Covalent and Ionic Bonding Lab Unit Name Exercise # Two of the characteristics that differentiate covalently bonded compounds from ionically bonded compounds are solubility and melting point. In this investigation, you will test these two properties of different compounds in order to predict the type of bonding present in each. Given the following compounds: potassium dichromate K 2 Cr 2 O 7 Para dichlorobenzene C 6 H 4 Cl 2 nickel (II) sulfate NiSO 4 butanol C 4 H 9 O silicon dioxide SiO 2 Test the solubility in water by adding some of the chemical to a test tube containing about two fingers of water and report the solubility qualitatively as soluble, insoluble, or partly soluble. Test the approximate melting point by placing a small amount of each of the solid compounds in a test tube and heating gently with a Bunsen burner. Note: Some of the chemicals may decrepitate (explode) upon strong heating, so increase the temperature gradually. If the compound melts below room temperature record low. If it melts easily under moderate heat, record moderate. If it melts or clumps together only under extreme heat, record high. If it never melts, record very high. In your conclusion, state your assessment of the composition of the compounds with regard to metallic or nonmetallic makeup and whether the bonding is ionic or covalent. Questions: 1. Did you heat the butanol? Why or why not? 2. Why is it difficult to decide the bonding for silicon dioxide? 3. Assume you have never heard of CO 2, but you have a periodic table. Compare CO 2 to SiO 2. What type of bonding do you predict for CO 2? Why? 4. Characterize the usual solubility, melting point and composition for ionically and covalently bonded compounds. 7-6