[試題] 99上 彭旭明 無機化學一 期中考
課程名稱︰無機化學一
課程性質︰必修
課程教師︰彭旭明
開課學院：理學院
開課系所︰化學系
考試日期（年月日）︰99/11/17
考試時限（分鐘）：130分鐘
是否需發放獎勵金：是
亮色表示下標
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
(圖略)
character table: D3h C2v D4h
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 140.109.66.56
推
11/25 07:25, , 1F
11/25 07:25, 1F