1. Which of the following statements about the group
5. Of the following species, which is diamagnetic in its
of elements consisting of Li, Na, K, Rb, and Cs is correct?
ground state? (3pts)
(a) The metals are all powerful oxidizing agents.
(b) They are known as the alkaline earth metals since
their hydroxides are strongly basic.
(c) They are usually stored under water since they react
readily with air.
(d) Each has the largest atomic radius of any element
6. The metallic gold has a unit cell of face-centered
in its period.
cube structure with one side of 8.16 A. What would the
atomic radius of gold be? (3pts)
(a) 1.80 A
(b) 2.80 A
2. The species in which of the following pairs have same
(c) 3.80 Â
(d) 4.80 A
(e) 5.80 A
(a) H2S and NH4*
(b) OF2 and CH4
(c) H3O+ and CF4
(d) XeF4 and BrF4
(e) H2O and SF4
7. What is the osmotic pressure of a 0.020 M of NaCl
aqueous solution at 25 °C when the osmotic pressure
of a 0.020 M sucrose aqueous solution at 25 °C is 0.30
3. Liquid ammonia does not exhibit which of the
following types of intermolecular interactions? (3pts)
(a) 0.62 atm
(b) 0.2 atm
I. Dipole-dipole interaction
(c) 0.25 atm
(d) 0.60 atm
II. Hydrogen bonding
(e) 1.0 atm
III. London(dispersion) force
IV. lonic boning
(a) I only
(b) II only
(c) III only
(d) IV only
8. At the same molality, which of the following solutions
(e) I, II, and III
has the lowest freezing point? (3pts)
4. Which of the following is the strongest oxidizing
10. Arrange the atoms or ions in decreasing order of size for each of the following groups. (6pts)
(a) Ba²*, CS*, l', Te2-
11. The following table shows the hydration energies and melting points for Li*, Na*, and K* ions.
Hydration Energy (kJ/mol)
(a) The hydration energy of an ion represents the change in energy that occurs when water molecules attach to a
M* ion. Describe the tendency of hydration energies for the three ions (Li*, Na*, and K"). (4pts)
(b) Lithium is the best reducing agent in water, but sodium and potassium react much more vigorously. Explain
using melting points in the table. (4pts)
12. Predict the molecular structures, bond angles, polarities and expected hybrid orbitals on the central atom for
each of the following compounds. (12pts)
13. Using the molecular orbital model, please give the electron configurations of F2°, F2 and F2: And predict their
bond orders and the relative bond lengths. And how many unpaired electrons do you expect in each species?
14. (a) Draw all the possible Lewis structures of cyanate ion (CNO*). (3pts)
(b) Choose the most stable one and explain the reason. (3pts)
15. X-ray with a wavelength of 2.63 A was used to analyze a crystal. The angle for first-order diffraction (n=1 in
the Bragg's equation) was 15.55°. What is the spacing (in pm) between the crystal planes, and what would be the
angle for second-order diffraction (n=2)? (4pts)
16. Please match the following vapor pressure diagrams with the solute-solvent combinations and explain your
(a) Hexane (Cothed and chloroform (CHCI)
(b) Acetone and water
(c) Hexane (Cother) and heptane (C>H16)
17. Refer to the following heating-cooling curve for water,
determine which of the heat of fusion (AH and the heat of
vaporization (AHa) is greater, and explain why? (4pts)
Heal added at coestant rate
18. Among the possible cubic unit cells of a crystalline solid, the face-centered cubic unit cell shows the largest
packing efficiency, which is the volume occupied by the components in the total volume.
(a) Find the percentage of the volume occupied by the components in the face-centered cubic unit cell. The
components are assumed to be complete spheres. (3pts)
Find the numbers of tetrahedral and octahedral holes per each face-centered cubic unit cell. (3pts)
(c) In calcium fluoride (CaF2) crystal, the calcium ions form a face-centered cubic lattice and the fluoride ions occupy
the holes. What type of holes do the fluoride ions occupy? In this structure, how many fluoride ions surround one
single calcium ion? (3pts)
19. Seawater (1.000 kg) was heated to evaporate water. The mass percent of the remaining salt (34 g) components
are as follows;
mass percent (%)
(a) Find the total molal concentration of the ions dissolved in the seawater.
(b) Determine the freezing point of the seawater (freezing-point depression constant of water = 1.86 °C.kg /mol).
(c) How many grams of NaCI should be added to allow 1.000 kg of this seawater to freeze at -5.0 °C?
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