Electronic Structure Worksheet Answer Key
WORKSHEET 1
1) A 2) C 3) E 4) E 5) E 6) E 7) D 8) E 9) B 10) E 11) D 12) C 13) D 14) D
15) B 16) D
WORKSHEET 2
1) C 2) C 3) A 4) D 5) B 6) B 7) D 8) D 9) B 10) D 11) B 12) D 13) B 14) D 15) C
WORKSHEET 3
1) D 2) B 3) D 4) D 5) C 6) A 7) C 8) A 9) C 10) C 11) D 12) C 13) E 14) B 15) B 16) C
WORKSHEET 4
1a) 7.31 x 1014 s-1, b) 4.843 x 10-19 J 2a) K+, b) Cl-, c) O, d) N, e) O 3a) Rb, b) At, c) Fr
4a) XII, b) VIII, c) VII, d) V, e) I, f) II, g) X 5) D 6) C 7) D 8) A 9) D 10) B 11) D 12) C
WORKSHEET 5
1) Energy is quantized: electrons can only have certain energies. When an electron makes a
transition from a higher energy level to a lower energy level, the excess energy may be released in the
form of light. The frequency of the light depends on the energy difference between the levels. Since
electrons occupy only specific energy levels, only specific differences (and thus only certain
frequencies) will result. So you see line spectra corresponding to those frequencies.
2) n = 4 allows for 4 values of L
L = 0 corresponds to an s-orbital, the shape is speherical, there is 1 s-orbital
L = 1 corresponds to a p-orbital, the shape is dual-lobe along the 3 axes, there are 3 p-orbitals
L = 2 corresponds to a d-orbital, the shape is multi-lobe in the 3 planes, there are 5 d-orbitals
L = 3 corresponds to an f-orbital, the shape is multi-lobe in the 3 planes, there are 7 f-orbitals
3) n2, 2n2
4) IIA (Alkaline earth metals) 5a) ml, b) ms, c) n, d) l
6) energy transitions, ionization energy, excited state stability
7a) Ne, b) Mo, c) Pm, d) Mg, e) Ne
6
8) a) 5.8x10 m/s b) Photon energy is quantized. No electrons are ejected unless the photons have
the threshold energy or greater.
9) a) Same answer as question 1.
b) In a series, all transitions are from some higher energy level to the same final level. The final
energy level distinguishes one series from another.
c)
n=5
n=4
The lowest energy transition is equal to the lowest frequency transition.
n=3
For the Lyman series, the final state is n = 1.
n=2
n=1
d) In an absorption spectrum, energy is absorbed by the system to raise electrons from lower levels to
higher levels. The spectrum that results will have some part fo the input light subtracted out -- those
frequencies corresponding to the energy level gaps of the system. An emission spectrum is energy
being released in the form of light when electrons make tranisitions from higher levels to lower ones.
e) At room temperature, essentially all electrons are in the ground state. Thus they can make
transitions from the ground state to higher states (Lyman series). There are no electrons in excited
states so there are no transitions from excited state to excited state.
10) ∆x∆p ≥ h b) Electrons cannot be confined to specific orbits. c) The mass(momentum) of
macroscopic particles is so many orders of magnitude larger than that of Planks constant that the
uncertainty principle is not relevant (although its still valid).
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