CHY 115, HW #9
1. Which of the following frequencies corresponds to light with the longest wavelength?
a) 3.00 ´ 1013 s–1
b) 4.12 ´ 105 s–1
c) 8.50 ´ 1020 s–1
d) 9.12 ´ 1012 s–1
e) 3.20 ´ 109 s–1
2. When a strontium salt is ignited, it burns with a red flame. The frequency of the light given off by this flame is greater than
a) yellow light
b) infrared light
c) ultraviolet light
d) radio waves
3. A line in the spectrum of atomic mercury has a wavelength of 258 nm. When mercury emits a photon of light at this wavelength, the frequency of this light is
a) 8.61 ´ 10–16 s–1
b) 7.70 ´ 10–19 s–1
c) 1.16 ´ 1015 s–1
d) 77.3 s–1
4. What is the wavelength of a photon of red light (in nm) whose frequency is 4.64 ´ 1014 Hz?
a) 646 nm
b) 1.55 ´ 106 nm
c) 155 nm
d) 464 nm
5. Green light can have a wavelength of 512 nm. The energy of a photon of this light is
a) 1.02 ´ 10–31 J
b) 5.12 ´ 10–7 J
c) 3.88 ´ 10–19 J
d) 5.86 ´ 1014 J
e) 2.58 ´ 1018 J
6. Which one of the following types of radiation has the shortest wavelength, the greatest energy, and the highest frequency?
a) Ultraviolet radiation.
b) Infrared radiation.
c) Visible red light.
d) Visible blue light.
e) None, because short wavelength is associated with low energy and low frequency, not high energy and high frequency.
7. The four lines observed in the visible emission spectrum of hydrogen tell us that:
a) The hydrogen molecules they came from have the formula H4.
b) We could observe more lines if we had a stronger prism.
c) There are four electrons in an excited hydrogen atom.
d) Only certain energies are allowed for the electron in a hydrogen atom.
e) The spectrum is continuous.
8. In an investigation of the electronic absorption spectrum of a particular element, it is found that a photon having l = 500 nm provides just enough energy to promote an electron from the second quantum level to the third. From this information, we can deduce
a) the energy of the n = 2 level
b) the energy of the n = 3 level
c) the sum of the energies of n = 2 and n = 3
d) the difference in energies between n = 2 and n = 3
Use the following to answer questions 9,10. Consider the following portion of the energy-level diagram for hydrogen:
n = 4
–0.1361 ´ 10–18 J
n = 3
–0.2420 ´ 10–18 J
n = 2
–0.5445 ´ 10–18 J
n = 1
–2.178 ´ 10–18 J
9. For which of the following transitions does the light emitted have the longest wavelength?
a) n = 4 to n = 3
b) n = 4 to n = 2
c) n = 4 to n = 1
d) n = 3 to n = 2
e) n = 2 to n = 1
10. In the hydrogen spectrum, what is the wavelength of light associated with the n = 4 to n = 1 electron transition?
a) 5.96 ´ 10–25 nm
b) 1.46 ´ 103 nm
c) 1.03 ´ 107 cm
d) 2.04 ´ 10–18 m
e) 9.73 ´ 10–8 m
11. When a hydrogen electron makes a transition from n = 3 to n = 1, which of the following statements is true?
Energy is emitted.
Energy is absorbed.
The electron loses energy.
The electron gains energy.
The electron cannot make this transition.
a) I, IV b) I, III c) II, III d) II, IV e) V
12. When an electron in a 2p orbital of a particular atom makes a transition to the 2s orbital, a photon of approximate wavelength 669.5 nm is emitted. The energy difference between these 2p and 2s orbitals is a) 2.97 ´ 10–28 J
b) 2.97 ´ 10–19 J
c) 2.97 ´ 10–17 J
d) 1.33 ´ 10–31 J
13. In Bohr's atomic theory, when an electron moves from one energy level to another energy level more distant from the nucleus:
a) Energy is emitted.
b) Energy is absorbed.
c) No change in energy occurs.
d) Light is emitted
14. Which of the following statements best describes the Heisenberg uncertainty principle?
a) The exact position of an electron is always uncertain.
b) The velocity of an electron can only be estimated.
c) It is impossible to accurately know both the exact location and momentum of an electron.
d) The location and momentum of a macroscopic object are not known with certainty.
e) The location and momentum of a particle can be determined accurately, but not the identity of the particle.
15. Which of the following best describes an orbital?
a) space where electrons are unlikely to be found in an atom
b) space which may contain electrons, protons, and/or neutrons
c) the space in an atom where an electron is most likely to be found
d) small, walled spheres that contain electrons
e) a single space within an atom that contains all electrons of that atom
16. Which of the following is not determined by the principal quantum number, n, of the electron in a hydrogen atom?
a) The energy of the electron.
b) the minimum wavelength of the light needed to remove the electron from the atom.
c) The size of the corresponding atomic orbital(s).
d) The shape of the corresponding atomic orbital(s).
e) All of the above are determined by n.
17. If n = 2, how many orbitals are possible?
a) 3 b) 4 c) 2 d) 8 e) 6
18. The magnetic quantum number is related to the orientation of the orbital in space relative to the other orbitals in the atom. True or False?
19. How many electrons in an atom can have the quantum numbers n = 3, l = 2?
a) 2 b) 5 c) 10 d) 18 e) 6
20. How many electrons can be described by the quantum numbers n = 2, l = 2, ml = 1?
a) 0 b) 2 c) 6 d) 10 e) 14
21. What is the l quantum number for a 4p orbital?
a) 2 b) 1 c) 0 d) 3 e) more than one of the above