Chapter 7 7.3 Metallic Bonding Ionic & Metallic Bonding 1. LESSON REVIEW Use the diagram of metallic bonding to answer the following questions. 1. What is the name of the model of metallic bonding that is illustrated? 2. Why are the electrons in a metallic solid described as delocalized? 3. Which electrons from the metal make up the delocalized electrons? 4. Are the metal atoms that are shown cations or anions? How can you tell? 5. How do the metallic ions differ from the ions that exist in ionic solids? 6. Explain what holds the metal atoms together in the solid. 2. PROPERTIES OF METALS For each property, write yes if the property is characteristic of most metals, or no if it is not. If the property is a characteristic of metals, explain how metallic bonding accounts for the property. 7. Malleable 8. Brittle 9. Lustrous 10. High melting point 11. Low boiling point 12. Ductile 13. Poor conduction of heat 14. Good conduction of electricity
3. CHAPTER REVIEW 1. An ionic bond is a. attraction of an atom for its electrons. b. attraction of atoms for electrons they share. c. a force that holds together atoms that are oppositely charged. d. the movement of electrons from one atom to another. 2. The formula unit of an ionic compound shows the a. total number of each kind of ion in a sample. b. simplest ratio of the ions. c. numbers of atoms within each molecule. d. number of nearest neighboring ions surrounding each kind of ion. 3. The overall charge of a formula unit for an ionic compound a. a. is always zero. b. is always negative. c. is always positive. d. may have any value. 4. How many chloride (Cl) ions are present in a formula unit of magnesium chloride, given that the charge on a Mg ion is 2+? a. one-half b. one c. two d. four 5. Ionic bonds generally occur between a. metals b. nonmetals. c. a metal and a nonmetal d. noble gases 6. Salts are examples of a. nonionic compounds b. metals c. nonmetals d. ionic compounds 7. In electron transfer involving a metallic atom and a nonmetallic atom during ion formation, which of the following is correct? a. The metallic atom gains electrons from the nonmetallic atom. b. The nonmetallic atom gains electrons from the metallic atom. c. Both atoms gain electrons. d. Neither atom gains electrons. 8. In general, metals react by: a. losing valence electrons. b. gaining valence electrons. c. sharing valence electrons. d. sometimes gaining and sometimes losing valence electrons. 9. Metals typically are a. good conductors of electrical current. b. malleable. c. ductile. d. all of the above 10. Metals are good conductors of electricity because they a. form crystal lattices. b. contain positive ions. c. contain mobile valence electrons. d. form ionic bonds. 11. A metallic bond is a bond between a. valence electrons and positively charged metal ions. b. the ions of two different metals. c. a metal and nonmetal. d. none of the above 12. An atom of the element M forms a stable ion in an ionic compound with chlorine having the formula MCl 2. In this compound, the ion of element M has a mass number of 66 and has 28 electrons. a. What is the identity of the element? b. How many neutrons does the ion have? 13. Which of the following compounds are most likely not ionic? Circle them. a. H 2O b. Na 2O c. CO 2 d. CaS e. SO 2 f. NH 3 14. For each ionic formula, identify the A-group number to which the element X belongs. a. CaX b. Al 2X 3 c. MgX 2 d. X 3N e. XF f. XS
Chapter 8 Covalent Bonding 8.1-8.2 Molecular Compounds 1. LESSON REVIEW bonds form when atoms share one or more pairs of. Sharing of electrons is another way for atoms to achieve the gas electron. Atoms may share pair, two pairs, or pairs of electrons depending on their electron need. When atoms share one pair of electrons, a covalent bond results. In a double covalent bond, atoms share electrons between them. Group elements form diatomic molecules by sharing two pairs of electrons. Nitrogen gas is a molecule that is formed when Nitrogen atoms share pairs of electrons between them. The type of elements that usually form covalent bonds are the. When only one atom contributes both the electrons for bonding, a covalent bond results. 2. COVALENT BONDING 1. Classify each of the following as an atom, diatomic molecule, or a molecular compound. a. Be b. CO 2 c. N 2 d. CO 2 e. N 2 f. O 2 g. H 2O h. CO i. H 2O j. Ne k. CO l. Cu Atoms: Diatomic Molecules: Molecular Compound: 2. Give the number of valence electrons in N, As, Br, and Se. Predict the number of covalent bonds needed for each of these elements to satisfy the octet rule. Valence # Covalent bonds Element Element Valence electrons # Covalent bonds needed electrons needed 3. Draw electron dot structures for each of the following molecules. a. Chlorine b. Bromine c. Iodine 4. The following molecules have single covalent bonds. Draw an electron dot structure for each molecule. a. H 2O 2 b. PCl 3
3. MOLECULAR FORMULA 1. Identify the number and kinds of atoms present in a molecule of each compound. a. Ascorbic acid (Vitamin C) C 6H 8O 6 b. Sucrose (table sugar) C 6H 12O 11 c. Trinitrotoluene (TNT) C 7H 5N 3O 6 4. LESSON REVIEW 1. The electron dot structure for hydrogen sulfide, H 2S, is H S H H S H H S H H H S a. b. c. d. 2. Which of these elements does not exist as a diatomic molecule? a. I b. F c. H d. He 3. Which one of the following compounds is not covalent? a. SCl 2 b. KCl c. HCl d. S 2Cl 2 4. How many valence electrons does an atom of any halogen have? a. 1 b. 2 c. 4 d. 7 5. A diatomic molecule with a triple covalent bond is a. N 2. b. Br 2. c. H 2. d. O 2. 6. A molecule of nitrous oxide, N 2O, contains all of the following except a. a coordinate covalent bond b. a triple bond. c. a double bond. d. nonbonding pairs of electrons. 7. Which of the following compounds is not ionic? a. NaI b. CaCl 2 c. CO 2 d. Na 2O 8. Which of these compounds would not have covalent bonds? a. NO 2 b. K 2O c. N 2O 4 d. H 2O 2 8. A covalent bond forms a. when an element becomes a noble gas. b. when atoms share electrons. c. between metals and nonmetals. d. when electrons are transferred from one atom to another. 10. A molecule with a single covalent bond is a. CO 2 b. F 2 c. NO d. N 2 11. When H + forms a bond with H 2O to form hydronium ion, H 3O +, this bond is called a coordinate covalent bond because a. both bonding electrons come from the oxygen atom. b. it is an especially strong bond. c. the electrons are equally shared. d. the oxygen no longer has eight electrons surrounding it. 12. Which of the following molecules has one lone pair of electrons? a. CH 4 b. HCl c. H 2O d. NH 3 13. What is the electron dot structure for the polyatomic ion OH? a. b. c. d.
Chapter 7 8.3 Molecular Geometry Ionic & Metallic Bonding Polar Molecules & Molecular Geometry Complete the following table using the electronegativity values from page 181 of your textbook and molecular shapes on page 243. Compound Polar bonds or nonpolar bonds? Lewis Dot Structure Molecular Geometry (Shape) NI 3 I-N-I I - Bond(s) N-I ΔEN for N-I Bond = 0.5 Moderately polar pyramidal CO 2 H 2 O CH 2 O NH 3 CH 4
Chapter 7 8.4 Polar Bonds & Molecules Ionic & Metallic Bonding 1. LESSON REVIEW is the ability of an atom to attract electrons when the atom is in a compound. When atoms bond, the more electronegative atom attracts electrons strongly and acquires a slightly charge. The difference in electronegativity between two atoms determines the character of the between them. A large difference in electronegativity between the atoms makes the bond polar, whereas, a very small difference makes the bond. 2. PROBLEMS IN BOND POLARITY 1. Part A: What is the most probable type of bond for each electronegativity difference range? Electronegativity Difference Range Most Probable Type of Bond 0.0 0.39 0.40 0.89 0.90 1.69 1.70 Atom 1 Atom 2 Electronegativity Difference (ΔEN) Bond Type Nonpolar Covalent (NPC), Moderately Polar Covalent (MPC), Very Polar Covalent (VPC), or Ionic (I) Arsenic Cobalt Sulfur Bromine
Germanium Silicon Potassium Nickel Barium Hydrogen Calcium Iron Selenium Fluorine Nitrogen Oxygen Tin Oxygen Sulfur Carbon 2. Part B Directions: Draw the Lewis Dot Structure for each compound below. Then, label each bond (bonds between 2 atoms there could be more than one bond in each compound) as either nonpolar covalent (NPC), moderately polar covalent (MPC), very polar covalent (VPC), or ionic (I). a. H 2O b. CH 4 H O very polar H c. NaCl d. PF 3 3. Part C Directions: With which elements could the following atoms, calcium and sulfur, bond with in order to create each of the 4 bond types with the elements given. Thought process for number 15: If Boron bonds with Iodine, the electronegativity difference would be greater than 1.7, so the bond would be ionic. If Boron bonds with oxygen, the electronegativity difference would be between 0.9 and 1.69, so the bond would be very polar covalent. If Boron bonds with Sulfur, the electronegativity difference would be between 0.4 and 0.89, so the bond would be moderately polar covalent. If Boron bonds with Phosphorus, the electronegativity difference would be between 0.0 and 0.39, so the bond will be nonpolar covalent. Element I VPC MPC NPC Boron Iodine Oxygen Sulfur Phosphorus Calcium Sulfur