GENERAL CHEMISTRY EXAM NO.2
TOPICS: Electronic Structure and the Periodic Table
I. Multiple Choice. Write your answers beside the each number. Use capital letters. Choose the letter of the best answer. Show computations (if applicable). NO SOULTION, NO CREDIT. (2 points each)
1. The Navy uses electromagnetic radiation of extremely long wavelengths to communicate with submerged submarines. The Navy's ELF (Extremely Low Frequency) systems emit 76 s-1 radiation from facilities located in Wisconsin and Michigan. What is the wavelength of this radiation (in meters)?
A. 2.1 ´ 10-7 m
B. 3.9 × 106 m
C. 2.3 × 1010 m
D. 1.3 ´ 10-3 m
E. 2.5 ´ 103 m
2. The lowest frequency available on a radio's AM dial is 570 kHz. What is the wavelength of this light?
A. 1.8 ´ 10-7 m
B.1.8 × 10-6 m
C.1.9 × 10-3 m
D.5.3 × 102 m
E. 5.3 × 104 m
3. A microwave oven emits radiation at a frequency of 6.00 × 1010 Hz. What is the wavelength of this light?
A. 3.98 × 10-23 m
B. 1.67 × 10-11 m
C. 5.00 × 10-3 m
D. 2.00 ´ 10-2 m
E. 2.00 ´ 10-1 m
4. Many hand held laser pointers emit 650 nm light. What is the frequency of this light?
A. 2.2 × 10-15 Hz
B. 5.1 × 10-3 Hz
C. 2.0 × 102 Hz
D. 1.5 × 106 Hz
E. 4.6 × 1014 Hz
5. Green laser pointers emit radiation at 532 nm. What is the frequency of this radiation?
A. 8.12 ´ 1013 Hz
b. 5.64 × 1014 Hz
c. 1.60 ´ 1015 Hz
d. 9.10 × 1015 Hz
e. 1.60 × 1016 Hz
6. Some digital cordless phones operate at 2.4 GHz (1 GHz = 109 Hz). What is the energy, in joules, of a single 2.4 GHz photon?
A. 8.3 ´ 10-35 J
B. 1.6 × 10-24 J
C. 5.4 × 10-19 J
D. 0.96 J
E. 0.13 J
7. A helium-neon (or HeNe) laser emits light at 632.8 nm. What is the energy of a single photon from this laser?
A. 3.139 × 10-19 J
B. 2.111 × 10-15 J
C. 1.263 × 10-11 J
D. 4.741 × 104 J
E. 1.897 × 105 J
8. When Cs-137 decays, it emits gamma radiation. The energy of one photon is 1.06 × 10-13 J. What is the wavelength of this radiation?
A. 1.87 × 10-12 m
B. 2.08 × 10-12 m
C. 2.44 × 10-12 m
D. 1.88 × 10-11 m
E. 1.58 × 10-10 m
9. The energy required to break one mole of hydrogen bonds in H2(g) is 436 kJ. What is the longest wavelength of light that is capable of breaking this bond?
A. 91.7 nm B. 103 nm
C. 192 nm D. 208 nm
E. 274 nm
10. Which of the following sets of quantum numbers refers to a 3p orbital?
A. n = 3, =0, m = 0, ms = + ½
B. n = 3, = 1, m = -1, ms = + ½
C. n = 3, = 2, m = 1, ms = + ½
D. n = 3, = 3, m = -2, ms = + ½
E. n = 3, = 3, m = 3, ms = + ½
II. TRUE or FALSE. Right minus wrong. Write T if the statement is TRUE and F if the statement is FALSE. If the statement is FALSE underline the word/s that make/s the statement FALSE. (20 pts)
1. If the following regions of the electromagnetic spectrum will be arranged in order from longest to shortest wavelength, the arrangement should be radio > microwave > visible > ultraviolet > gamma ray.
2. The wavelength of light is directly proportional to its frequency.
3. The frequency of light is directly proportional to its energy.
4. The energy of a photon of light is inversely proportional to its wavelength.
5. The frequency of light is directly proportional to the speed of light (in a vacuum).
6. The wavelength of light is inversely proportional to the speed of light (in a vacuum).
7. According to the Bohr model for the hydrogen atom, the energy necessary to excite an electron from n = 5 to n = 6 is less than the energy necessary to excite an electron from n = 3 to n = 4.
8. There are 3 orbitals in the following quantum numbers: n = 4, l = 1.
9. n = 4, = 3, m = -2, ms = - ½ set of quantum numbers refers to a 4f orbital.
10. 1s22s22p63s23p63d54s2 is the ground state electron configuration of 25Mn.
III. Identification. Write the answer (must be properly spelled and no acronyms) described in each item below. (20 pts)
1. It predicts that when several orbitals of equal energy are available, as in a given subshell, electrons enter singly with parallel spins.
2. Elements and compounds with unpaired electrons are attracted to a magnetic field.
3. It is an equation that can be solved to find the probability of finding an electron in a region of space.
4. This principle states that no two electrons from a given atom can have the same four quantum numbers.
5. Place the following atoms in order of increasing size: Al, Cl, Mg, O, and P.
6. Place the following ions in order of increasing radius: Al3+, F-, Mg2+, and N3-
7. Place the following atoms in order of increasing ionization energy: C, N, and Si.
8. Among the five atoms Na, P, Cl, K, or Kr, it has the largest atomic radius.
9. It is the most electronegative element on the periodic table.
10. It is the energy needed to lose the valence electron.
IV. Complete the table below. (20 pts)
Trend in the Periodic Table (decreasing or increasing) | ||
Left to Right | Top to Bottom | |
Ionization Energy | ||
Electronegativity | ||
Electron Affinity | ||
Atomic Radius | ||
Metallic Property | ||
V. Answer the following questions:
Nos. 1 to 4 (10 pts)
1. Write the correct orbital diagram for phosphorus.
2. Write the correct orbital diagram for Ca2+.
3. Write the correct orbital diagram for Fe2+ using core method.
4. What is the ground state electron configuration of 24Cr using the rectangular method?
5. Give the set of quantum numbers for each: (5 points each)
a. Barrium
b. Cesium
c. Bromine
d. Gallium
6. Identify the atom or ion with the following electronic configuration: (5 points each)
a. [Ar]3d10
b. [Ar]3d104s2
c. 1s22s22p63s23p63d54s1
d. [Rn]5f67s2
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