→ firepeter :雖說是王瑜但是是鄭原忠XD 06/24 19:49
推 firepeter :轟哥要不要考慮改一下標題?? 不然可能會誤導 06/24 22:41
→ a3225737 :喔也是可以拉 06/24 23:24
※ 編輯: a3225737 來自: 140.112.250.115 (06/24 23:26)
推 q510724 :真的好多題@@ 06/24 23:31
課程名稱︰化學鍵
課程性質︰化學系大一以上選修
課程教師︰王瑜、鄭原忠
開課學院：理學院
開課系所︰化學系
考試日期（年月日）︰2011.06.24
考試時限（分鐘）：120mins
是否需發放獎勵金：是
（如未明確表示，則不予發放）
試題 :
Chemical Bonding Spring, 2011
Final Exam Date: 6/24/2011
1. (8%) Determine the structure and point group of each of
the molecules in the following:
(a) SO3 2-, (b) BrF5, (c) ClF3, and (d) XeO3.
2. Consider SO3 2-, BrF5, and ClF3. Answer the following questions
for each of the molecules.
(a) (4% x 3) Find the reducible representation for σ bonding in
the system and determine the irreducible symmetry representations.
Find the possible a hybridizations for the center atom.
List all possible hybridizations in your answer.
(b) (4% x 3) Sketch the symmetry-adapted ligand-group orbitals,
and use the results to construct a qualitative MO energy-level
diagram. Explain your selection of hybrids and energy levels.
3. Consider SO32 and ClF3, and answer the following questions for each of them.
(a) (4% x 2) Find the symmetry of the π-bonds in the molecule.
(b) (3% x 2) Determine the center atom hybridizations that can
contribute to it bonding, and use the results to construct a
qualitative MO energy-level diagram for π-bonding in the molecule.
4. (10%) Consider the π-bonds in the cyclopentadienyl ring.
Use the 5 p orbitals as a basis set and answer the following
questions using a character table:
(a) How do they separate into subsets of symmetry-equivalent
orbitals? Give the symmetry representation of each subset.
(b) Sketch the 5 symmetry-adapted linear combinations (SALCs)
and the energy level diagram.
5. Molecular orbitals of the H4 molecule can be constructed
using SALC of the four H is orbitals. Answer the following questions:
(a) (4%) Determine the MOs for a tetrahedral H-1s molecule.
Sketch the energy level diagram and the electronic configuration.
(b) (4%) Consider a “butterfly” H4 molecule whose Ha-Hb bond is
slightly shortened and Hc-Hd bond is slightly stretched.
Determine its MOs, and sketch the energy level diagram for the
butterfly H4. You need to correctly assign the order of the energy levels,
(c) (4%) Draw a correlation diagram between the MOs of the two H4 molecules.
You needto correctly assign the relative energies.
Hint: use two symmetry planes to correlate the MOs.
(d) (4%) Do you expect the H4 molecule to exhibit Jahn-TelIer effects?
Do you expect the H4+ molecular cation to exhibit stronger or weaker
Jahn-Teller effects? Use the correlation diagram to explain your
answer.
For simplicity, we ignore all other distortions.
6.(10%) Determine how the d-orbitals split in each of the
following environments:
(a) trigonal bipyrarmidal, and
(b) square planar.
Use a crystal field model to determine the relative energies.
7. (12%) Consider bonding between ligands and d-orbitals of a
transition metal ion in an octahedral complex.
Generally, the spcctrochcmical series follows the trend:
1,2-dimethylcyclo-3,5-hexadiene (two methyl group is in the same direction)
to
(2E,4Z,6E)octatriene
π-donor ligands < pure σ-donor ligands < π-acceptor ligands.
Apply the 1igand field theory to explain the trend.
8.(10%) The thermal electrocyclic reaction of hexatriene
derivatives follows the following regioselection ruies:
Construct correlation diagrams for both the conrotatory and
disrotatory reaction mechanism to explain the selectivity.
9. (3% each) Briefly explain the trends depicted in the following:
(a) Wavelength of absorption maxima in LTV/Vi:
[CoC16]3- > [CoF6]3 -> [Co(NH3)6]3+ > [Co(CN)6]3-.
(b) Energy of absorption maxima in UV/Vis:
[Ir(NH)6]3+ > [Rh(NH3)6]3+ > [Co(NH3)6]3+.
(c) Lattice enthalpies of metal oxides with octahedral coordinations:
VO> TiO> MnO > CaO.
(d) v(CO) values in IR spectrum:
[Mn(CO)6]+> [Cr(CO)6]> [V(CO)6]> [Ti(CO)6]2-.
(e) Metal-Metal bond length:
[Re2Cl8]2-> [Re2Cl8]- > Re2C18.
(f) In octahedral [Cu(OH2)6]2+
Axial Cu-O bond length> Equatorial Cu-O bond length
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◆ From: 140.112.24.14
※ 編輯: a3225737 來自: 140.112.24.14 (06/24 18:42)