Physical Chemistry True/False – Flashcards
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Consider a particle in a 1D box extending from 0 to L, Ψ = cos(kx) can be an eigenfunction if the value of k is restricted to certain discrete values based on the boundary condition.
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False
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The resulting tunneling wavefunction through a rectangular barrier where V>E has a greater wavelength than the incoming wavelength.
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False
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The high resolution of STM rests on the fact that the vacuum gap between the metal tip and the scanned conducting surface can be considered a 1D box.
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False
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The quantum harmonic oscillator eigenfucntions are also eigenfunctions for the raising and lowering operators.
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False
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A particle moves freely on the surface of a sphere. Since the motion is in 3D, the quantum state of the particle is determined by 3 quantum numbers.
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False
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Consider a diatomic molecule freely rotating in 3D. Its motion is modeled by the particle on a sphere model. Once the values of l and ml are known, we can determine the angular momentum vector.
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True
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The vector notation of the ground state for the quantum harmonic oscillator is identical to the vector notation of the ground state for the particle in a box.
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True
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Consider the quantum harmonic oscillator, matrix notations of Hamiltonian, quantum number operator, and raising and lowering operators are all diagonal.
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False
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Considering a free particle in a 3D box, the box is defined as 0<x<Lx, 0<y<Ly, 0<z<Lz, and with no lengths equal, the frist excited state has a degeneracy of 3.
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False
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Considering a free particle in a 3D cube, the degeneracy of the states is either 1 or 3.
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False
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For any individual particle with a spin s=1/2, not only electrons, the magnitude of the spin angular momentum is (3/4)^1/2 hbar
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True
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We need to consider the Pauli Exclusion Principle when there is more than one electron in the atom. Therefore the physics origin of the Pauli Exclusion Principle is electron-electron interaction.
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True
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Some atoms have electronic configurations as the exception of the n+l rule. Those electron configurations are against the requirement of minimizing the total atomic energy.
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False
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Fine structures (line splitting) in atomic spectra and the Stern-Gerlach experiment are both experimental evidence of electron spin.
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True
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S value in a two 2p electron atomic system can be 0 or 1.
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False
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Spin-orbit interaction exists in atoms other than H. Atoms with a larger Z are expected to have a larger spin-orbit interaction.
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True
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Hund's first and second rules are both consequences of electron-electron repulsion in multi-electron atoms.
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True
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In multi-electron atoms, the total energy of the ground state is detemined by n, S, L, and J.
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True
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Compared to the Hamiltonian for an H atom, the Hamiltonian for multi-electron atoms has only one more potential energy term, which describes electron-electron interaction.
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False
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The allowed values of the total orbital angular L of a two electron system can be obtained by using L=l1+l2, l1+l2-1, ..., |l1-l2|
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True
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S value of an atomic system of two 2s electrons can be 0 or 1.
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False
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A shell of an atom consists of all the orbitals of a given value of n (n is the principle quantum number). For example, orbitals with n=2 together (2s2p) is a shell. A subshell of a shell of an atom consists of all the orbitals with the same value of n but different values of l. For example, 2p is a subshell. How many orbitals are in each shell and subshell? A. n, l B. 2n, 2l C. n^2, l^2 D. n^2, 2l=l
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D
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Origin of the Pauli Exclusion Principle is A. electron-electron interaction B. Existence of electron spin C. Existence of multiple electrons in the atom considered D. The exchange anti-symmetry property of fermions
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D
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The Stern-Gerlach experiment detects discrete traces of atoms when an external magnetic field is applied. For a given atom, we expect to see a number of traces equal to A. 2 B. 2J+1 C. 2S+1 D. 2L+1
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B
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When the spectral lines of the H spectrum are examined at very high resolution, they are found to be closely-spaced double lines (doublets). This splitting is due to A. Electron-electron repulsion B. Electron-proton attraction C. Spin-orbit interaction D. An external magnetic field applied to H
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C
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In theory, all particles, even a baseball in motion, can have wave-particle duality.
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True
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For a particle on a ring, the allowed values for the quantum number n is different compared to the case for a particle in a 1D box. This is because of the different boundary conditions for the solutions of the Schrodinger equations.
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True
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Deuterium atoms can also be treated like H-like ions with Z=2
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False
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Ψ(r,R,t) = sum(Ψj(r,R)Ψ(R,t)), where j is the index for nucleus states, r indicates the positions of the electrons while R indicates the positions of the nucleus. This equation indicates that the Born-Oppenheimer approximation is assumed.
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True
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In principle, we can choose any mathematical function as a trial function when using the Variational Method.
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True
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When applying LCAO to a molecule, the number of the molecular orbitals must be equal to the total number of the atomic orbitals that are used in the linear combination.
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True
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The molecular potential energy function V(R) = Ee + Vn = Ee + e/(4*pi*sig0)*(1/R) is the established base on LCAO
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False