CHEM 1411
practice problem of chap7
1. *What is the frequency of 500nm?(the speed of light is 3.00 x 10 8m/s)
(a) 6.00 x 10 18
(b) 12.00 x 10 14
(c) 6.00 x 10 14
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(d) 8.00 x 10
(e) 6.00 x 10
2. *Calculate the energy (in joules) associated with the photons if the wavelength of the X
rays is 0.154 nm.
(a) 1.29 x 10 -15 (b) 8.70 x 10 -15 (c)1.29 x 10 -18 (d)4.35 x 10 -25 (e)2.79 x 10 -30
3. Which of the following statements concerning four quantum numbers is correct?
(a) The angular (i.e. azimuthal) quantum number, l, determines the energy of an electron in a
hydrogen atom and in a many-electron atom.
(b) The principle quantum number, n, determines the shape of an orbital.
(c) The electron spin quantum number, ms, determines the orientation of an orbital in space.
(d) The magnetic quantum number, ml, determines the size of an orbital.
(e) The principle quantum number, n, determines the size of an atom.
4. What values of the angular momentum (l) quantum numbers are allowed for n=4?
(a) -4,-3,-2,-1 (b) 0.1,2,3,4 (c)0,1,2,3
(d) -3,-2,-1,0,1,2,3
5. Which of the following four quantum numbers (n, l, ml, ms) does not represent an
electron in a 3d orbital?
(a) (3, 2, -1, +½)
(b) (3, 2, -2, -½)
(c) (3, 2, 0, -½)
(d) (3, 2, +1, +½)
(e) (3, 1, +1, +½)
6. *Which of the following sets of quantum numbers in an atom is acceptable?
(a) (1, 0, +½, +½)
(b) (3, 2, -2, -½)
(c) (3, 3, 0, -½).
(d) (4, 2, +3, +½)
(e) (3, 0, +1, +½)
7. Which of the following is a correct ground-state electron configuration?
(a) Al: 1s22s22p43s23p3
(b) B: 1s22s22p5
(c) F: 1s22s22p6
(d) Mg: 1s22s22p63s13p1
(e) Cl: 1s22s22p63s23p5
8. *How many unpaired electrons are present in Al?
(a) 1
(b) 2
(c) 3
(d) 4
(e) 5
9. Which family of elements is characterized by having an ns2np1outer-electron
configuration?
a) Group IA
b) Group IIA c) Group IIIA d) Group II B
10. What is the maximum number of electrons in an atom that has the quantum numbers as
n=2, l=0, ms= +½?
(a) 1
(b) 2
(c) 3
(d) 4
(e) 5
11. *Which of the following violates the Pauli Exclusion Principle?
(a) ↑ ↑__ ↑↑
(b) ↑ ↑↓ ↑_
(c) ↑ ↑↓ ↓_
(d) ↑↓_ __ ↑ _ ↑_ ↑_
(e) ↑_ ↑__ ↑ _ ↓_ ↑↓_
12. *Which of the following violates the Hund’s rule?
(a) ↑ ↑__ ↑↑
(b) ↑ ↑↓ ↑_
(d) ↑↓_ __ ↑ _ ↑_ ↑_
(e) ↑_ ↑__ ↑ _ ↓_ ↑↓_
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(c) ↑ ↑↓ ↓_
13. What is the maximum number of electrons in an atom that has the quantum numbers as
n=4, ml= +1?
(a) 2
(b) 4
(c) 6
(d) 8
(e) 10
14. Which of the following is paramagnetic?
(a)He (b)Be (c)B (d)Ne (e)Mg
15. *Calculate the wavelength (in nm) of a photon emitted by a hydrogen atom when its
electron drops from the n = 5 state to the n = 3 state.
(a) 264
(b)1280
(c)4598
(d) 6789
(e)9056
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