1. The first ionization energy of I(g) is 1008 kJ/mol. The electron affinity of I(g) is -295 kJ/mol. Calculate the enthalpy change for the following reaction. I+(g) + I-(g) = 2 I(g) A. -713 kJ B. 1303 kJ C. -1303 kJ D. 713 kJ
2. Which of the following atoms and ions are isoelectronic ? A. F- and O B. Na+ and F C. Na- and F- D. Na- and Mg
3. The anion with the electron configuration 1s2 2s2 2p6 is: A. Ne B. O-2 C. S-2 D. Mg2+
4. The reaction of magnesium metal with nitrogen, at elevated temperatures, A. forms MgN. B. gives Mg3N2. C. produces MgO. D. yields MgN2.
5. The electron configuration [Ar]3d5 is the ground state configuration of: A. V B. Fe3+ C. Mn2+ D. both B and C
6. Arrange Na, Mg, Al, and K in order of decreasing first ionization energy. A. Na > Mg > Al > K B. K > Na > Mg > Al C. Mg > Al > Na > K D. Al > Mg > Na > K
7. Using the periodic table as a guide, arrange Li, Be2+, and Be in order of increasing size. A. Be2+ < Be < Li B. Be < Li < Be2+ C. Li < Be < Be2+ D. Be < Be2+ < Li
8. Which of the alkaline earth metals will react with water at room temperature to give the metal hydroxide and hydrogen gas ? A. Be and Mg B. Rb and Cs C. Sr and Ba D. F and Cl
9. Which of the following species, represented as Lewis structures (with charges not shown), are ions ?
A. 1 and 4
B. 1, 3, and 4
C. 3 and 4
D. 2 and 310. Consider the pairs: 1. LiF and LiBr 2. MgO and Na2O Which member of each pair would have the highest lattice energy ? A. LiF, MgO B. LiBr, MgO C. LiBr, Na2O D. LiF, Na2O
11. In XeF2, the central Xe atom has more than eight valence electrons around it because A. Xe is a noble gas atom. B. Xe is a very big atom. C. Xe has accessible d orbitals to hold additional electrons. D. All of the above.
12. Which of the following resonance forms is the most important in describing the bonding of OCN- ?
13. Use the information in the following table of bond energies to calculate the enthalpy (heat) of combustion of one mole of ethylene, C2H4, in excess molecular oxygen to form gaseous water and carbon dioxide. Bond Energy Bond Energy Bond Energy (kJ/mol) (kJ/mol) (kJ/mol) C-H 414 O2 498 O-H 463 C-C 348 C-O 351 H-H 436 C=C 611 C=O 799 C-=C 837 C-=O 1072 A. +505 kJ B. -1550 kJ C. -2343 kJ D. -1287 kJ
14. The correct Lewis electron dot structure for hydrazine, N2H4 (a neutral molecule), is:
15. In the possible resonance form of BrO3- shown below, what is the formal charge on the bromine atom ?
A. 0
B. +1
C. -1
D. +216. How many electrons (bonding and lone pairs) are shown in the correct Lewis structure of the SCN- ion ? A. 14 B. 16 C. 15 D. 18
17. Which one of the following is the correct Lewis structure for BF3 ?
18. What is the hybridization of the carbon atoms in H-C=C-H ? A. sp B. sp4 C. sp3 D. sp2
19. The C-O-C bond angle in H3COCH3 is approximately: A. 90o B. 109o C. 120o D. 180o
20. The molecular geometry of BrF5 is: A. octahedral. B. square pyramidal. C. trigonal bipyramidal. D. linear.
21. In valence bond theory, the orbitals of the nitrogen atom in NCl3 are: A. sp hybridized. B. not hybridized. C. sp3 hybridized. D. sp2 hybridized.
22. Which of the following molecules are polar ? A. XeO2 and NO B. NH3 and PCl5 C. XeO2 and I2 D. I2 and NO
23. From molecular orbital theory, what are the bond order and number of unpaired electrons in N22- ? A. Bond order = 3; unpaired electrons = 0 B. Bond order = 5/2; unpaired electrons = 2 C. Bond order = 2; unpaired electrons = 0 D. Bond order = 2; unpaired electrons = 2
24. Which of the following is not true about ethylene(H2C=CH2) ? A. The carbon carbon bond order is 2. B. The carbon atoms are sp2 hybridized. C. The carbon atoms are connected by two pi bonds. D. The molecule is planar.
25. A molecular orbital is a wave function of an electron in a(n) ____________. Molecular orbitals are formed by combining valence orbitals of _____________. A. atom; an atom B. molecule; an atom C. atom; all atoms D. molecule; all atoms