课程名称︰无机化学一 课程性质︰必修 课程教师︰彭旭明 开课学院：理学院 开课系所︰化学系 考试日期（年月日）︰99/11/17 考试时限（分钟）：130分钟 是否需发放奖励金：是 亮色表示下标 1.Suppose that you begin at a distance far from the nucleus on the z axis, through the nucleus to a distance far on the -z axis. Howmany nodal surface would you pass through for each of following orbitals:(5%) (a)1s (b)2s (c)3pz (d)4d3z^2-r^2 (e)5fz(5z^2-3r^2) 2.Determine the point group of the following atomic orbitals, including the signs on the orbital lobes:(5%) (a)px (b)dxy (c)dx^2-y^2 (d)dz^2 (e)fxyz 3.For the 3pz and 4pxz hydrogen-like atomic orbitals, sketch the following:(6%) (a)The radial function R. (b)Theradial probability function a0r^2R^2. (c)Contour maps of election density. 4.The 4fz(x^2-y^2) orbital has the angular function Υ=(constant)z(x^2-y^2)/r^3.(8%) (a) How many radial nodes does does this orbital have? (b) How many angular nodes does it have? (c) Write equations to define the angular nodal surfaces. What shapes are these surfaces? (d) Sketch the shape of the orbital, and show all radial and angular nodes. 5.A sample calculation in this chapter showed that, according to Slater's rules , a 3d electron of nickel has a higher effective nuclear charge than a 4s electron. Is the same true for early forst-row transition metals? Using Slater's rules, calculate S and Z* for 4S and 3d electron of Sc and Ti, and comment on the similarities or differences with Ni. 6.When XeF4 is reacted with a solution of water in Acetonitrile solvent, the product F2OXeN三CCH3 is formed. Applying a vacuum to crystals of this product resulted in slow removal of Acetonitrile: F2OXeN三CCH3 -> XeOF2 + CH3CN Propose structures for F2OXeN三CCH3 and XeOF2.(4%) 7.Provide explaneations for the following:(10%) (a) Methanol, CH3OH has a much higher boiling point than methyl mercaptan, CH3SH. (b) Carbon monoxide has slightly higher melting and boiling points than N2. (c) The ortho isomer of hydroxybenzoic acid [C6H4(OH)(COOH)] has a much lower melting point than meta and para isomers. (d) The boiling points of the noble gases increase with atomic number. (e) Acetic acid in the gas phase has a significantly lower pressure (approaching a limit of one half) than predicted by the ideal das law. (f) Mixtures of acetone and chloroform exhibit significant negative deviations from Raoult's law, which states that the vapor pressure of a volatile liquid is proportional to its mole fraction. For example, an equimolar mixture of acetone and chloroform has a lower vapor pressure than either of the pure liquid. (g) Carbon monoxide has a greater bond-dissociation energy(1072 kJ/mol) than molecular nitrogen (945 kJ/mol). 8.Give the lewis structures, sketch the shapes and determine the point group of the following molecules.(15%) (a) H2SO4 (b) HNO3 (c) H3PO4 (and 1H is bounded to P) (d) Allene (H2C=C=CH2) (e) N2H4 9.Ethylene has D2h symmetry.(10%) (a) List all the symmetry operations of ethylene. (b) Write a transformation matrix for each symmetry operation that describes the effect of that operation in the coordinates of a point x, y, z. (c) Using the characters of your transformation matrices, obtain a reducible representation. (d) Using the diagonal elements of your matrices, obtain three of the D2h irreducible representations. (e) Show that your irreducible representations aremutually orthogonal. 10.For the following molecules, determine the number of IR-active C-Ostretching vibrations: (12%) (a) [ferrous pentacarbonyldichloride] cis form. (b) [ferrous pentacarbonyldichloride] trans form. (c) iron pentacarbonyl 11.Why the dioxygen molecule is paramagnetic with two unpaired electrons?(6%) 12.For the molecule PCl5: (9%) (a) Using the character table for the point group of PCl5, determine the possible type(s) of hybrid orbitals that can be used by P in forming bonds to the five Cl atoms. (b) What type(s) of hybrids can be used in bonding to the axial chlorine atoms? To the equatorial chlorine atoms? (c) Considering your answer to part b, explain the explain the experimental observation that the axial P-Cl bonds (219 pm) are longer than the equatorial bonds (204 pm). 13.BF3 is often describe as a molecule in which boron is electron deficient, with an electron count of six. However, resonance structures can be drawn in which boron has an octet, with delocalized π electrons.(8%) (a) Draw these structures. (b) Find the molecular orbital in Figure 1 (next page) that shows this delocalization and explain your choice. (c) BF3 is the classic Lewis acid, accepting a pair of electrons from molecules with lone pais. Find the orbital in Figure 1 that is the acceptor; explain your choice, including why it looks like a good election acceptor. (d) What is the relationship between the orbitals identified in Parts b and c? 14.Answer the following questions: (10%) (a) Calculate and display the molecular orbitals for linear and cyclic H3+. (b) Which species is more likely to exist(i.e., which is more stable?) 15.Answer the following question: (10%) (a) Draw the molecular orbital diagram for CO molecule. (b) CO is a good ligand as a σ-base and π-acid. Find the orbitals that acts as the σ-base and the π-acid of CO molecule. ====================================The end====================================== Figure 1 : molecular orbitals of BF3 (图略) character table: D3h C2v D4h --

※ 发信站: 批踢踢实业坊(ptt.cc) ◆ From: 140.109.66.56