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課程名稱︰無機化學一
課程性質︰必修
課程教師︰鄭淑芬
開課學院：理學院
開課系所︰化學系
考試日期（年月日）︰2012/12/26
考試時限（分鐘）：110
是否需發放獎勵金：是
（如未明確表示，則不予發放）
試題 :
1.(a) Show the molecular orbital energy diagram of the diatomic molecule C2.
Also, indicate the bonding, antibonding and non-bonding orbitals(if any).
(6%)
(b) The bond dissociation energy of C2 (599 kJ/mol) decreases slight on
forming C2+ (513 kJ/mol) and increases greatly on forming C2-
(818 kJ/mol). Why? (6%)
2.(a) Give the symmetry lables for the 4s-, 3d- and 4p-orbitals of the central
metal atoms in [CoBrCl5]3-, trans- and cis-[CoCl2(en)2]+
(where "en" is "ethylenediamine"). (9%)
(b) How many Co-Cl stretching vibration peaks do you expect to see in the
IR spectra of these three ions, respectively? (15%)
3.(a) Work out the symmetry-adapted linear combinations of p-orbitals to form
π-orbitals for cyclobutadiene. (8%)
(b) Sketch the shapes of these π-orbitals. (4%)
(c) Show the molecular orbital energy diagrm of the π-orbitals for
cyclobutadiene. (2%)
4.(a) Utilizing simple Huckel M.O. theory with the p-orbitals which form
π-orbitals of O3 as a basis set, set up the secular determinant and
compute the energies of the π-orbitals of O3 in terms of α (Coulomb
integral) and β (Overlap integral). (10%)
(b) SO2 is isoelectronic to O3. Compare the energies of its π-M.O. with
those of O3. (5%)
(c) SO2 is both a Lewis acid and a Lewis base. When reacting with trimethyl
amine, which orbital do you expect SO2 to use? and from S or from O atom
sides? Explain. (5%)
5.(a) Show the molecular orbital energy diagrams and LCAOs for H3 in
(i) linear and (ii) triangle planar geometries. (10%)
(b) Draw the "Walsh diagram" for H3. (5%)
(c) What will be the most stable geometries for H3+, H3, and H3- species,
respectively? (3%)
6. Arrange the following ions in order of increasing acidity, and account
for the trend. (10%)
[Na(H2O)n]+, [Al(H2O)6]3+, [Mn(H2O)6]2+, [Fe(H2O)6]3+, [Ni(H2O)6]2+
7.(a) What is the definition of "proton affinity"(PA)? Write the equation
with NF3. (2%)
(b) Write a thermochemical cycle from which you can obtain the "proton
affinity" of NF3, from the bond dissociation energies of N-H in NF3H+,
and ionization energies(IEs) of H and NF3. (5%)
(c) Explain why the PA of NH3 is greater than that of PH3, based on the
above cycle. (2%)
(d) Explain why the difference in PAs between NH3 and NF3 is greater than
that between PH3 and PF3. (5%)
------------------------------------------------------------------------------
Compound NH3 NF3 PH3 PF3
------------------------------------------------------------------------------
PA(kJ/mol) 854 1122 789 910
IE of M in MX3 984 984 965 965
(kJ/mol)
------------------------------------------------------------------------------
Given information:
Orbital Potential Energies(atomic number 1~36, 1s, 2s, 2p, 3s, 3p, 4s, 4p)
Correlation Tables of D3h & Td
Character table of C2, C3, C4, C2v, C3v, C4v, D3, D2h, D3h, D3d, Oh, Td
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