※ [本文转录自 NTU-Exam 看板] 作者: abacada (力量的极限) 看板: NTU-Exam 标题: [试题] 90年下 周必泰 普通化学甲下期中考partA 时间: 01/27/2005 01:13:45 Thu 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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