Review: Periodicity and Bonding


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Periodicity Review

  1. Know the terms: Noble gases, representative elements, alkali metals, alkaline earth metals, halogens, transition metals, and inner transition metals.
  2. Know the definition and the trends in the periodic table for atomic size, electronegativity, and ionization energy.
  3. Which is larger Cl or Cl-1. Explain.
  4. Rank the isoelectronic series from smallest to largest in size: Sr+2, As-3, Br-1, Kr, Rb+1, Se-2. Explain your reasoning.
  5. As you go across the 3rd period, what is the trend in ionic sizes and in melting point?
  6. Write the balanced reaction for each of the following:
    1. sodium metal reacting with water
    2. Cl2 reacting with Br-1
    3. iodine reacting with chloride ion
    4. liquid bromine reacting with water
    5. potassium reacting with bromine
    6. silver ion reacting with bromide ion
  7. What is the trend for the reactivity of the alkali metals? Give the reasons for it.
  8. What is the trend for the reactivity of the halogens? Give the reasons for it.

Bonding Review

  1. How many valence electrons in each of the following atoms?
    a) Br   b) C   c) Na   d) Se   e) S-2   f) Na+1
  2. Write the electron dot diagram for each of the elements in question 1.
  3. Using the electron dot diagrams for sodium and oxygen, show how sodium oxide will form.
  4. How many electrons do each of the following gain or lose to form an ion?
    a) Br   b) I   c) Ca   d) Se
  5. Why do the elements listed in question 4 want to gain or lose electrons?
  6. Write the formula for the ionic compound that forms when each pair of elements combine.
    a) magnesium and bromine   b) aluminum and sulfur   c) lithium and phosphorus
  7. Name the compounds in question 6.
  8. Explain the difference between an ionic bond and a covalent bond.
  9. Explain the difference between a polar and nonpolar bond. What type of bonds are these, ionic or covalent?
  10. Draw electron dot structures (Lewis dot diagrams) for the following compounds.
    a) CHCl3   b) NH3   c) O3   d) PO4-3   e) HCN   f) XeF4   g) PCl5   h) SO3   i) NO   j) SF6
  11. Identify the shape for all the molecules in question 10, except f).
  12. State whether each molecule will be polar or nonpolar in question 10.
  13. Which is harder to break, a single bond or a double bond?
  14. Draw the resonance structures for SO3.
  15. What is the VSEPR theory and how does it predict the shape of a molecule?
  16. List the following pairs in order from least ionic character to most ionic character.
    a) O - F   b) Cl - O   c) K- O   d) Li - N
  17. State whether each of the following compounds are ionic or covalently bonded.
    a) NaCl   b) CH4   c) K2O   d) Li3N   e) H2O
  18. Explain how Na3PO4 has more than one type of bonding in it.
  19. What is hydrogen bonding?
  20. Explain how HCl can become a liquid (explain the intermolecular forces).
  21. Explain how I2 can be a solid when it does not have a dipole to attract another molecule.
  22. Why will CaCl2 dissolve in water?
  23. Will CH3OH dissolve in water? Why or why not?
  24. Will C8H18 dissolve in water? Explain.
  25. If either 23 or 24 did not dissolve in water, what might be an alternative? Why?
  26. Draw the electron dot diagram and show the partial charges for the following:
    a) HCl   b) H2S   c) CCl4
  27. CCl4 has polar bonds in it. Why is the molecule nonpolar?
  28. A given substance is a white solid at 25 °C. It melts at 450 °C and will conduct an electric current when molten. What type of a substance might this be?
  29. A white solid melts at 1500 °C and will not conduct electricity, even when molten. Classify the substance as best you can from these properties.
  30. Compare the bond angles in CH4, NH3, and H2O. Explain the differences.
  31. List C2H6, C2H2, and C2H4 in order of shortest C - C bond to longest. Give your reasoning.
  32. Knowing the following bond energies in kJ mol-1: C-H = 413, C-Cl = 339, find the energy required to make CHCl3 from its atoms.
  33. Knowing the following bond energies in kJ mol-1: C-H = 413, Cl-Cl = 239, F-F= 154, C-F = 485, C-Cl = 339, H-F = 565, and H-Cl = 427, find the enthalpy of the reaction:
    CH4 (g)   +   2 Cl2 (g)   +   2 F2 (g)   -->   CF2Cl2 (g)   +   2 HF (g)   +   2 HCl (g)



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