CHE 105 - Mid-Term Examination II - 7 March 1996 University of Kentucky - Department of Chemistry
1. Calculate the wavelength of light emitted when the electron in a hydrogen atom undergoes a transition from an n = 6 to an n = 3 orbital (RH = 1.097 x 107 m-1).
A. 5.47 x 10-7 m B. 1.82 x 10-19 m C. 1.09 x 10-6 m D. 2.24 x 1014 m
2. How many electrons can exist in the subshell with n = 2 and l = 3?
A. 2 B. 14 C. 10 D. 0, there is no such subshell.
3. Arrange the following subshells in order of increasing energy.
3p 3d 4s 4p
A. 3p < 3d < 4s < 4p B. 3p < 4s < 3d < 4p C. 3p < 4s < 4p < 3d D. 4p < 4s < 3d < 3p
4. How many unpaired electrons are in a ground state nitrogen atom?
A. 1 B. 2 C. 3 D. 5
5. In a many electron atom, the energy of the electron depends on which quantum numbers?
A. n B. n and l C. n and l and ml D. n and l and ml and ms
6. When light impinges on aluminum metal, no electrons are emitted if the wavelength of light is longer than 295 nm. What will the kinetic energy of an ejected electron be if 200 nm wavelength light is used?
A. 3.20 x 10-19 J B. 3.20 x 10-28 J C. 6.29 x 10-34 J D. 6.29 x 1019 J
7. The possible values of the magnetic quantum number (ml) of a 4f electron are
A. -1, 0, +1 B. -2, -1, 0, +1, +2 C. 0, +1, +2, +3 D. -3, -2, -1, 0, +1, +2, +3
8. The orbital diagram for an oxygen atom in its ground state is
9. Which of the following are isoelectronic with Cl-?
A. Ar, S B. Ar, K+ C. F-, Br- D. P-, S-
10. Arrange the following in order of increasing size
F, F-, O2-
A. One cannot compare sizes of atoms and ions. B. F- < F < O2- C. O2- < F- < F D. F < F- < O2-
11. The electron configuration for the valence electrons of the alkaline earth elements is
A. ns2np1, n > 2 B. ns1, n > 1 C. ns2, n > 1 D. ns1, n > 0
12. Electron affinity is
A. the energy required to add an electron to a gaseous atom in its ground state. B. the energy required to remove an electron from a ground state gaseous atom. C. the energy change (positive or negative) associated with the addition of an electron to a gaseous atom in its ground state. D. always negative.
13. Which of the following will react with cold water to produce H2 gas?
A. Be B. C C. Ba D. Mg
14. Arrange the following in order of increasing first ionization energies Cl, Al, Mg, P, Si, S
A. Mg < Al < Si < P < S < Cl B. Cl < S < P < Si < Al < Mg C. Al < Mg < Si < S < P < Cl D. Cl < P < S < Si < Mg < Al
15. The electron configuration for the Fe3+ cation is
A. [Ar]4s23d6 B. [Ar]4s23d3 C. [Ar]3d5 D. [Ar]4s23d9
16. Noble gases are exceptionally stable and chemically unreactive because:
A. They have a closed electron shell configuration. B. They are all gases. C. They are descendents of royalty. D. They have an even number of electrons.
17. Which of the following is a correct Lewis structure of SO2?
18. Consider the pairs:
1. LiF and LiBr 2. MgO and Na2O
Which member of each pair would have the highest lattice energy?
A. LiF, Na2O B. LiBr, Na2O C. LiBr, MgO D. LiF, MgO
19. For the Lewis structure
A. both zero B. both 1 C. 0, -1 respectively D. +1, -1 respectively
20. The molecule HCN has __________ bonding and _________ lone pair electrons.
A. 4, 6 B. 8, 2 C. 6, 4 D. 4, 4
21. Which Lewis structure is the most probable for the OCN- ion?
22. Which of the following are incorrect Lewis structures?
23. The Lewis structure
24. Which of the following is true?
A. The closer together the electronegativity of two atoms the less polar the bond. B. Electronegativity increases from right to left on the periodic table. C. Ionization energy and electronegativity are a measure of the same phenomena. D. Both (A) and (C) are true.
25. Lattice energy is
A. the energy required to separate one mole of an ionic crystal into isolated gaseous ions. B. always endothermic. C. the energy released when an ionic compound is formed. D. (A) and (B) are correct.
10 July 1996