Answers to Study Guide for CHEM 101 Test 2, Fall 2007
Chapters 7, 8 & 9

  1. For each of the compounds below, draw the Lewis structure.

    1. PBr3, tripodal, sp3



    2. CCl4, tetrahedral, sp3



    3. NH3, tripodal, sp3



    4. BF3, trigonal planar, sp2



    5. PF5, trigonal bipyramid, sp3d



    6. SF4, wedge, sp3d



    7. SeCl6, octahedral, sp3d2



    8. I3-, linear, sp3d



    9. XeF4, square planar, sp3d2



    10. ICl3, t-shaped, sp3d



    11. ClO3-, trigonal planar, sp2 plus d orbital interactions in p bonds. Only one of three possible resonance structures is shown.





  2. Properly name the following compounds.

    1. MnSO4 manganese (II)sulfate

    2. AlPO4 alluminum phosphate

    3. P2O3 diphosphorus trioxide

    4. K3PO4 potassium phosphate

    5. KClO3 potassium chlorate

    6. Sc2S3 Scandium (III) sulfide

    7. N2O5 dinitrogen pentoxide

    8. Ca(NO3)2 calcium nitrate

    9. CoNO3 cobalt (I) nitrate

    10. FeSO4 iron (II) sulfate

  3. Draw Lewis structures for these more complex molecules:

    1. hydrazine


    2. ethylene


    3. propylene



  4. Define:

    1. valence electrons - reactive electrons above the previous noble gas, likely to participate in bonding

    2. bonding pair of electrons - a pair of electyrons shared between two atoms to form a bond

    3. lone pair or non-bonding pair (electrons)- a pari of electrons resident on an atom that does not participate in bonding

    4. electronegativity - the attraction an element has for the electrons in a bond with a different element

    5. first ionization energy - the energy needed to remove the outermost electron of an atom

    6. quantum number - a number designating an allowed energy

    7. n - prinicpal quantum number, n = 1, 2, 3,...

    8. l - angular momentum (azimuthal) quantum number, l = 0 to n -1

    9. ml - magnetic quantum number, ml = -l to +l

    10. ms - spin quantum number, ms = +1/2 or -/12

    11. Pauli exculsion priciple - each electyron in an atom, ion or molecule has a unique set of quantum numbers

    12. Hund's rule - electrons are placed in orbitals with the same (degenerate) energies with parallel spins prior to pairing electrons in orbitals

    13. periodicity - the property that similar chemical properties recur within the periodic table. Such properties lead to groups or families (vertical columns) on the periodic table.

    14. period - a horizontal row on the periodic table.

    15. group or family - a vertical column on the periodic table.
    16. isoelectronic - having the same electron configuration.
    17. paramagnetic - containing at least one unpaired electron.
    18. diamagnetic - containing no unpaired electrons.

  5. Predict the products for the reaction between the paired elements below.

    1. O and Li

      Li2O

    2. P and S

      P2S3 or P2S5

    3. S and F

      SF2, SF4 or SF6

    4. Al and F

      AlF3

    5. Mg and N

      Mg3N2


  6. What are the electron configurations for the elments below? Follow the Aufbau (building-up) principle.

    1. Mn = [Ar]4s23d5

    2. Se = [Ar]423d104s2

    3. Pr = [Xe]6s24f3

    4. Pb = [Xe]6s24f145d106p2

    5. As = [Ar]4s23d104p3

    6. Sr = [Kr]5s2

    7. In = [Kr]5s24d105p1

    8. He = 1s2

    9. Mg = [Ne]3s2

    10. Sc = [Ar]4s13d1

  7. Provide the quantum numbers for the last electron placed in each of the elements in problem above.

    1. n = 3, l = 2, ml = 2, ms = +1/2

    2. n = 4, l = 1, ml = -1, ms = -1/2

    3. n = 4, l = 3, ml = -1, ms = +1/2

    4. n = 6, l = 1, ml = 0, ms = +1/2

    5. n = 4, l = 1, ml = 1, ms = +1/2

    6. n = 5, l = 0, ml = 0, ms = -1/2

    7. n = 5, l = 1, ml = -1, ms = +1/2

    8. n = 1, l = 0, ml = 0, ms = -1/2

    9. n = 3, l = 0, ml = 0, ms = -1/2

    10. n = 3, l = 0, ml = 3, ms = +1/2

  8. Tell if each element in the problem two problems above is diamagnetic or paramagnetic.

    1. paramagnetic
    2. paramagnetic
    3. paramagnetic
    4. paramagnetic
    5. paramagnetic
    6. diamagnetic
    7. paramagnetic
    8. diamagnetic
    9. diamagnetic
    10. paramagnetic>

  9. Rationalize your way to the proper electron configurations for these exceptions to the Aufbau (building-up) principle

    1. Cr = [He]4s13d5

    2. Gd = [He]6s24f75d1

    3. Au = [He]6s14f145d10

    4. Pd = [Kr]5s04d10

    5. Mo = [Kr]5s14d5

  10. What is the trend for electronegativity?

    Increases traveling up a columns and increasing the farther right in a row, for the s and p blocks. For the d and f blocks a chart needs to be consulted.

    .
  11. What is the trend for first ionization energy?

    Increases traveling up a columns and increasing the farther right in a row.

  12. What is the trend for electron affinity?

    Increases traveling up a columns and increasing the farther right in a row for the absolute value of the electron affinity.

  13. Given the formula for the compound below in each example, predict the formula for the compound asked for

    1. If the formula for the oxide of aluminum is Al2O3, what would the formula for the oxide of indium, In, be?

      In2O3

    2. If the formula for the sulfide of beryllium is BeS, what would the formula for the sulfide of strontium, Sr, be?

      SrS

    3. If the formula for the nitride of sodium is Na3N, what would the formula for the phosphide (P3-) of sodium be?

      Na3P

    4. If the formula for the fluoride of of zinc is ZnF2, what would the formula for the fluoride of cadmium, Cd, be?

      CdF2

    6. If the formula for the oxide of titanium is TiO2, what would the formula for the oxide of zirconium, Zr, be?

      ZrO2

  14. Are the compounds below ionic or covalent?

    1. CH4

      covalent

    2. Na2S

      ionic

    3. SO3

      covalent

    4. Na2SO3

      ionic

    5. MgH2

      ionic

    6. P2S3

      covalent

    7. BF3

      covalent

    8. AlBr3

      ionic

    9. SeO2

      covalent

    10. CO2

      covalent

  15. Determine the formal oxidation state of the underlined element in the compounds and ions below:

    1. ClO4-

      cl + 4(-2) = -1
      cl - 8 = -1
      cl -8 + 8 = -1 + 8
      cl = +7

    2. P2O3

      oxygen wants two electrons, so o = -2

    3. Fe2(SO4)3

      2(fe) + 3(-2) = 0
      2(fe) - 6 = 0
      2(fe) - 6 + 6 = 0 + 6
      2(fe) = +6
      fe = +6/2 = +3

    4. PPF5

      p + 5(-1) = 0
      p - 5 = 0
      p - 5 + 5 = 0 + 5
      p =+5

    5. ClO2-

      cl + 2(-2) = -1
      cl - 4 = -1
      cl - 4 + 4 = -1 + 4
      cl = +3

    6. SnS2

      sn + 2 (-2) = 0
      sn - 4 = 0
      sn - 4 + 4 = 0 + 4
      sn = +4

    7. PO43-

      p + 4(-2) = -3
      p - 8 = -3
      p -8 + 8 = -3 + 8
      p = +5

    8. ClO-

      cl + -2 = -1
      cl + -2 + 2 = -1 + 2
      cl = +1

    9. Li3N

      N would like to gain three electrons, so -3.

    10. CO32-

      c + 3(-2) = -2
      c - 6 = -2
      c - 6 + 6 = -2 + 6
      c = +4

  16. Label all the columns and parts of the periodic table on the blank periodic table below: