2002. 4.30
Total:200%
1.Definition and Explanation (5%*10=50%)
a)Based on standing wave and de Broglie relation briefly explain energy
levels have to be quantized when treating the particle motion as a wave in
a fixed length, one dimensional box where potential energy=0
b)Heisenberg's uncertainty principle
c)From quantum mechanic point of view, explain why an orbital can hold only
two electrons, and they must have opposite spins
d)In one dimensional wave motion where potential energy is assumed to be
constant(=V), write down the corresponding Schrodinger equation for a
particle with mass m, and also define the Hamiltonian
e)Briefly explain self-consistent field method for obtaining the orbitals of
a polyelectronic atom
f)Qualitatively depict the radial distribution of electron density to
explain the penetration effect for 3s, 3p, 3d and 4s
g)The differences between LE and MO models
h)Write down the full name as well as explain the VSEPR model
i)Explain the difference between electronegativity and electron affinity
j)Explain molecularity and termolecular reaction
2.1 Debye(1D) is equivalent to 3.336×10^-30 Cm. The dipole moment and bond
distance for HF are measured to be 1.83D and 0.917埃, respectively.
Calculate the percentage of the ionic bonding for HF. (10%)
3.a)Write down all possible Lewis structures for XeO3(including the resonance
forms) and determine the most stable form from the formal charge (5%)
b)Write three possible Lewis structures of N2O and determine the most
unstable form based on the formal charge (5%)
4.Draw the Lewis structures and geometry for the following molecules and
predict whether each is polar or nonpolar (15%)
a)HOCN, b)XeF2, c)SO2, d)I3 -, e)S2O3 2-, f)BeCl2, g)KrF4
5.Assume that NO has similar MO diagram with O2. For species NO, NO+, NO- and
NO2- (5%*3=15%)
a)Write down the MO diagram for NO
b)Ordering the bond energy energy in terms of bond order for the above
species
c)Which have(has) the diamagnetic property?
6.In general, what types of information can rotational, vibrational and
electronic spectroscopy provide? Predict their order of energy in terms of
wavelengths (i.e.UV-Vis, X-ray, IR...etc) (10%)
7.Assume that OH molecule is analogous to the HF molecule and that the MOs
result from the overlap of a pz orbital from osygen and 1s orbital of
hydrogen (the O-H bond lies along the z axis) (10%)
a)Knowing that only 20 orbitals of oxygen interact significantly with the 1s
orbital of hydrogen, complete the MO energy-level diagram for OH. Place
the correct number of electrons in the energy levels
b)Estimate the bond order for OH, OH+ and OH-
↑
│
│ ──
│ 1s
│
energy ── ── ──
│ 2pz 2px 2py
│
│ ──
│ 2s
│ AO of Molecular AO's of oxygen
hydrogen orbitals
8.Assume that six electrons are confined to a one dimensional box 5.64×10^-10
m in length. If the Pauli exclusion principle holds, calculate the
radiation necessary to promote the highest-energy electron into the first
excited state (Planck's constant h=6.62×10^-34 Js (10%)
9.Similar to N2 the bond order of CO is three
a)Assign formal charges to each atom in CO. Write down the dipole moment
(using the symbol defined in the text book) for CO (5%)
b)In the MO model, binding MOs place more electron density near the more
electronegative atom. Antibonding MOs place more electron density near
the less electronegative atom in the diatomic molecule. Use the MO model
to predict which atom of CO should form bonds with a variety of metals
which have outer electrons in d orbitals (5%)
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作者: abacada (力量的極限) 看板: NTU-Exam
標題: [試題] 90年下 周必泰 普通化學甲下期中考partB
時間: Fri Jan 28 00:51:18 2005
單選題(3%*20=60%)
1.Li(s) → Li(g) heat of sublimation of Li(s)=166 KJ/mol
HCl(g) → H(g) + Cl(g) bond energy of HCl=427 KJ/mol
Li(g) → Li(g)+ + e- ionization energy of Li(g)=520 KJ/mol
Cl(g) + e- → Cl-(g) electron affinity of Cl=-349 KJ/mol
Li(g)+ + Cl-(g) → LiCl(s) lattice energy of LiCl(s)=-829 KJ/mol
H2(g) → 2H(g) bond energy of H2(g)=432 KJ/mol
Calculate the net change in energy for the reaction:
2Li(g) + 2HCl(g) → 2LiCl(s) + H2(g)
a)363 KJ
b)-562 KJ
c)-179 KJ
d)-73 KJ
e)non of above
2.Which of the following is the correct order of molecules from most to least
polar?
a)CH4 > CF2Cl2 > CF2H2 > CCl4 > CCl2H2
b)CH4 > CF2H2 > CF2Cl2 > CCl4 > CCl2H2
c)CF2Cl2 > CF2H2 > CCl2H2 > CH4 = CCl4
d)CF2H2 > CCl2H2 > CF2Cl2 > CH4 = CCl4
e)CF2Cl2 > CF2H2 > CCl4 > CCl2H2 > CH4
3.Which of the following is NOT a valid resonance structure for N3-?
.. .. .. -
a) [ Ｎ＝Ｎ─Ｎ: ]
'' ''
.. -
b) [ Ｎ≡Ｎ─Ｎ: ]
'' ''
.. -
c) [:Ｎ—Ｎ≡Ｎ: ]
''
.. .. -
d) [ Ｎ＝Ｎ＝Ｎ ]
'' ''
4.Which molecule has the smallest bond angle?
a)O3
b)OF2
c)HCN
d)SSe3
5.Which element does E represent in the formula below?
:Ｏ: a)Si
.. ∥ - b)S
[:Ｏ－Ｅ－Ｈ] c)As
'' ∣ d)Xe
:Ｏ: e)B
''
6.Consider the compound crotonaldehyde
H H H H
| | | |
H─C1─C2─C3─C4─O
|
H
How many nonbonding electrons appear in the Lewis structure of this molecule
?
a)2
b)4
c)6
d)8
e)10
7.In the following Lewis structure
Ｈ Ｈ Ｈ
｜ .. ｜ │ ..
Ｈ─Ｃ─Ｏ─Ｃ─Ｃ≡Ｃ─Ｃ＝Ｎ─Ｈ
│ '' │1 2 3 4
Ｈ Ｈ
What is the hybridization of the oxygen atom and carbon atoms 1,2,and 4,
respectively?
O C-1 C-2 C-4
a)sp3 sp3 sp sp2
b)sp sp3 sp sp
c)sp sp2 sp sp2
d)sp2 sp3 sp2 sp3
e)sp sp3 sp2 sp
8.Which of the following has the largest bond energy?
a)O2
b)O2 -
c)O2 2-
d)O2 +
e)O2 2+
9.Order the molecules C2, B2, H2 and N2 from the shortest to largest bond
length
a)H2, N2, C2, B2
b)N2, C2, B2, H2
c)C2, N2, H2, B2
d)C2, B2, H2, N2
10.Which statement is NOT true?
a)Electrons are never found in an antibonding molecular orbital
b)All antibonding molecular orbitals are higher in energy than the atomic
orbitals of which they are composed
c)Antibonding molecular orbitals have electron density mainly outside the
space between the two nuclei
11.Which of the following statements about the CO3 2- ion is FALSE?
a)The orbitals on the carbon atom are sp2 hybridized
b)The ion is expected to be diamagnetic
c)One C-O bond is shorter than the other
d)The ion has a total of 24 electrons
12.A wave function is expressed as
Ψ = (1/81√(3π))((Z/a0)^(3/2))(27-18σ+2σ^2)e^(-σ/3)
specify the corresponding orbital?
a)1s
b)2s
c)2pz
d)2px
e)3dz^2
f)3s
13.The hybridization of the central atom in SeF4 is
a)sp
b)sp2
c)sp3
d)dsp3
e)d2sp3
14.Use the energy-level diagram for the hydrogen atom. Select the TRUE
statement.
a)A transition from n=5 to n=3 involves greater energy than one from n=4 to
n=2
b)The transition from n=4 to n=2 emits radiation of longer wavelength than
the transition from n=5 to n=1
c)All transitions from states for which n>1 to the n=1 state involve the
absorption of energy by the atom
d)A transition from n=2 to n=∞ corresponds to the ionization energy of the
H atom
15.Which of the following is a reasonable criticism of the Bohr model of the
atom?
a)It makes no attempt to explain why the negative electron does not
eventually fall into the positive nucleus
b)It does not adequately predict the line spectrum of hydrogen
c)It does not adequately predict the ionization energy of the valence
electron(s) for elements other than hydrogen
d)It does not adequately predict the ionization energy of the first energy
level electrons for one-electron species for elements other than hydrogen
e)It shows the electrons exist outside the nucleus
16.Which is the electron configuration of the element with atomic number 109?
a)[Rn]7s2 5f14 6d7
b)[Rn]7s2 6f14 6d1 7p6
c)[Rn]8s2 7f14 6d7
d)[Xe]7s2 5f14 6d7
e)[Re]7s2 6d7
17.An element with the electron configuration [Kr]4d10 5s2 5p2. The formula
for the fluoride of E is most likely
a)EF14
b)EF4
c)EF
d)EF6
e)EF8
18.Choose the pair of sequences that arranges, respectively, the atomic radius
and ionization energy from the smallest to largest?
a)S, O, F and F, O, S
b)F, S, O and O, S, F
c)S, F, O and S, F, O
d)F, O, S and S, O, F
19.What is the probability of finding a particle in a one-dimensional box in
energy level n=4 between x=L/4 and x=L/2? (L is the length of the box)
a)12.5%
b)25%
c)33%
d)37.5%
e)50%
20.A first-order reaction is 35% complete after 55 minutes. What is the
lifetime of this reaction?
a)530 min
b)0.028 min
c)88 min
d)128 min
e)176 min
f)none of these
解答:edabb baeaa cfdbc abdbd