Name ______

Unit 3 Chemistry – Chemical Bonding and Molecules Assignment

Types of Chemical Bonds Lesson: (22 pts)

1. Complete the following chart: (9 pts)

Characteristics / Covalent Bond / Metallic Bond / Ionic Bond
Conductivity
Malleable
Non-conductive

2. Bonds between metals and nonmetals tend to be ionic, but bonds between nonmetal atoms tend to be covalent. Explain why this is true, using your understanding of electronegativity and ionization energy for these groups of elements. (2 pts)

3. Seth wants to create a device to transmit an electrical current. He has th following materials; pure water (H2O), brass (Cu3Zn2) foil, solid calcium chloride (CaCl2), solid sugar (C12H22O11), pure methane (CH4), and a Bunsen burner.

Describe two ways he could use these materials to transmit electricity. Assume that he has access to all necessary glassware and other equipment. Explain your choices using the properties of ionic, covalent , and metallic substances. (5 pts)

4. Compare and contrast ionic, covalent, and metallic bonds. Identify at least one similarity or difference between each pair of bond types (Ionic-covalent, ionic-metallic, metallic-covalent).(6 pts)

Ionic Bonding Lesson: (6 pts)

1. Describe the ammonium ion, NH4+, and the sulfate ion, SO42-. What compounds would these ions form with potassium and fluoride ions? Write the formula units for the resulting compounds. (3 pts)

2. Compare a crystal lattice with a molecule. What does the formula unit Al(OH)3, tell you about the compound aluminum hydroxide? (1 pt)

3. Explain what lattice energy is and how it affects the properties of ionic compounds. Describe the general properties of ionic compounds. (2 pts)

Metallic Bonding Lesson: (3 pts)

1. How is the electron sea model of metallic bonding different from the band theory? How are they the same? Give at least one similarity and one difference between the models. (2 pts)

2. Copper (Cu) is often used for electrical wiring and cooking pans. However, iron (Fe) is much more common on Earth than copper. Why might copper be used instead of iron, if iron is easier to obtain? (1 pt)

Covalent Bonding Lesson: (15 Pts)

1. Using the diagram below, answer the following questions:

  1. Identify arrow pointing to bonding electrons. (1 pt)
  1. Identify arrows pointing to nonbonding electrons. (1 pt)
  1. Identify arrows pointing to structures containing sigma bonds. (1 pt)
  1. Identify arrows pointing to structures containing pi bonds. (1 pt)

2. Draw the Lewis structure for the following compounds. (8 pts)

a. I2
b. OF2
c. H2S
d. NI3
e. SCl2
f. PCl5
g. SO3

3. Explain what is wrong with the following structure. (1 pt)

4. Acetone and sodium chloride both have similar mass. Explain why their other properties differ. (2 pts)

  1. Acetone: C3H6O, melting point = -94°C, liquid at room temperature, low electrical conductivity.
  2. Sodium: NaCl, melting point = 880°C, solid at room temperature, high electrical conductivity.

Molecular Geometry Lesson: (17 pts)

1. Use the Lewis structure to predict the electron domain geometry of eachmolecule. (2 pts)

Lewis Structure / Electron Domain Geometry

2. Use the periodic table to determine the shape of the molecule represented by the following formulas. (4 pts)

Formula / Shape
a. CH2Cl2
b. PI3
c. NO2
d. SF6

3. Write in the number of lone pairs or atoms to complete each description below (4 pts)

  1. A molecule that has a trigonal-planar shape has ______lone pairs.
  2. A molecule that has a bent shape and a trigonal-planar electron domain shape has ______lone pairs.
  3. A molecule that has a trigonal-pyramidal shape has ______atoms and ______lone pair around the central atom.

4. Write in the name of the molecular geometry for each molecule described below. (4 pts)

  1. A molecule with two atoms and no lone pairs around the central atom has a ______shape.
  2. A molecule with four atoms and no lone pairs around the central atom has a ______shape.
  3. A molecule that has two atoms and two lone pairs around the central atom has a ______shape.
  4. A molecule that has five atoms and no lone pairs around the central atom has a ______shape.

5. Write the geometry of each type of hybrid orbital that forms. (3 pts)

  1. When one s- and one p-orbital mix, the resulting hybrid orbitals have a ______geometry.
  2. When one s- and two p-orbitals mix, the resulting hybrid orbitals have a ______geometry.
  3. When one s- and three p-orbitals mix the resulting hybrid orbitals have a ______geometry.

Intermolecular Forces Lesson: (8 pts)

Please read the article As Stick as a Gecko...but Ten Times Stronger, and then answer the following questions.

1. Explain how geckos climb glass. (2 pts)

2. Explain how scientists applied the knowledge of gecko feet to produce an adhesive. (2 pts)

3. Explain shear adhesion. (1 pt)

4. Definitions: (3 pts)

Term / Definition
hydrogen bonding
London dispersion forces
dipole-dipole forces