课程名称︰无机化学一 课程性质︰必修 课程教师︰郑淑芬 开课学院：理学院 开课系所︰化学系 考试日期（年月日）︰2012/11/28 考试时限（分钟）：160 是否需发放奖励金：是 （如未明确表示，则不予发放） 试题 : 1. Give the symmetry lables for the 4s-, 3d- and 4p-orbitals of the central metal atoms in [CrCl6]3- and [Co(en)3]3+. (where "en" is "ethylenediamine") (10%) 2.(a) Show the molecular orbital energy diagram of CO. Also indicate the bonding, antibonding and non-bonding orbitals (if any). (5%) (b) The UV photoelectron spectrum of CO is shown below. Assign the peaks to the corresponding electron transitions. (3%) (c) Taking CO as an example, how can one correlate the bonding character of the molecular orbitals by using UV photoelectron spectroscopy? (3%) (d) When forming dative bond with Lewis acid or coordinating with metal, which lone pair is the pair donates? Explain. (4%) 　　　 Ｘ ┌┐ 　　　 ｜ 　　　 ｜ 　　　 ｜ 　　　 ｜ 　　　 ｜　　　　　　　　　　　Ａ 　　　 ｜　　　　　　　┌－－－－－－－┐ 　　　 ｜ Ｂ 　　　 ｜ ｜　　　　　　　　　 　┌－－┐ 　　　 ｜ ｜｜｜ 　　　 ｜ ｜｜｜｜ ｜ 　　　 ｜ ｜｜｜｜｜｜ ｜ 　　　 ｜ ｜｜｜｜｜｜｜ ｜｜ ________________________________________________________ 14 16 18 20 ionization energy/eV 3.(a) Show the Lewis structure of [NO3]- ion. (3%) (b) Construct the π-molecular orbitals and the corresponding energy level diagram by using "symmetry adapted linear combination of atomic orbitals". (10%) (c) FNO2 is iso-electronic with [NO3]-. What will be the π-MOs and energy levels of FNO2? (5%) 4.(a) Show the "molecular orbital energy diagrams" and their "LCAOs" for AH2 molecule (A is a 2nd row element) (i) in linear and (ii) in bent geometries. (12%) (b) Draw the "Walsh diagram" for AH2. (5%) (c) Based on the "Walsh diagram", explain why the first excited state of BH2 is linear whereas that of BeH2 is bent. (4%) 5. Answer the following questions, with proper explanations. (15%) (a) Order of increasing acidity in aqueous solution HClO, HClO2, HClO3 (b) Order of increasing basicity toward BMe3 Py(pyridine), 2-MePy, 4-MePy (c) Order of proton affinity NH2(CH3), NH(CH3)2, N(CH3)3 (d) Order of increasing acidity toward NH3 BF3, BCl3, BBr3 (e) Order of increasing acidity in wate [Na(H2O)n]+, [Fe(H2O)6]3+, [Ni(H2O)6]2+ 6. Xenon difluoride, XeF2, can act as a Lewis base toward metal cations such as Ag+ and Cd2+. (a) In these cases, do you expect the XeF2 to exert its basicity through the lone pairs on Xe or those on F? Briefly explain your answer. (3%) (b) [Ag(XeF2)2]AsF6 and [Cd(XeF2)2](BF4)2 have both been synthesized. In which case, [AsF6]- or [BF4]-, do you expect the fluorines to act as a stronger Lewis bases? Explain briefly. (3%) 7. The absorption spectra of solutions containing I2 are solvent dependent, as shown below. (the spectra is same as text book: Gary L. Miessler & Donald A. Tarr, Inorganic Chemistry, fourth edition, p.189, Fig6.10, 1st, 3rd, 4th absorption spectra) (a) Assign the peak of I2 near 500 nm to the proper electron transition. Explain the shift of this peak in benzene and in methanol. (b) Define the charge transfer (CT) band. Explain the shift of the CT bands in methanol in comparison to that in benzene. (12%) 8.(a) Display the molecular orbital energy level diagram of BH3, and assign the symmetry representation of each molecular orbital. (6%) (b) Show how the frontier orbitals of BH3 and F- interact to form the [F‧BH3]- adduct-like anion. (6%) (c) How many B-H stretching vibration peaks do you expect to see in the IR spectra of BH3 molecule and that of the [F‧BH3]-, respectively? (6%) ------------------------------------------------------------------------------ Given information: Orbital potential energies (1s, 2s, 2p, 3s, 3p, 4s, 4p / atomic number 1~36) Correlation table of D3h and Td Character table of C3, C2v, C3v, D3, D2h, D3h, D3d, Oh, Td --

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