Name: ________ANSWER KEY__________________________ Date: ___________________________ Period: ________
Unit 5 Test Study Guide
Nuclear & Quantum Chemistry
Nuclear Equations
Write nuclear equations for the following scenarios:
1. Alpha emission by plutonium-239, one of the substances formed in nuclear power plants.
239
4
235
Pu
 He +
U
94
2
92
2. Beta decay by sodium-24, used to detect blood clots
24
0
24
Na

e
+
Mg
11
−1
12
3. Oxygen-15 undergoes positron emission, used to assess the efficiency of the lungs.
0
15
Pu  +1
He + 15
N
8
7
4. Copper-64 goes through electron capture, used to diagnose lung disease.
64
0
Cu + −1
e  64
Zn
29
30
5. A radioactive isotope is bombarded with an alpha particle to produce Polonium-209.
205
Pb + 42He  209
Po
84
82
6. A silver-117 undergoes three beta emissions before it reaches a stable nuclide. What is the final product?
117
0
0
0
117
Ag

e
+
e
+
e
+
Sn
47
−1
−1
−1
50
Complete the following nuclear equations and identify which type of nuclear decay it is.
90
90
0
7.
Sr

Y
+
+
e
This is ___beta decay____________.
38
39
−1
0
 17
O + + +1
e
8
8.
17
F
9
9.
222
Rn
86
10.
18
0
F + + −1
e
9
11.
235
U
92
12.
118
Xe
54
0
 118
I + + +1
e
53
13.
204
Sr
84
+
 218
Po + 42He
84
 18
O
8
 42He + 231
Th
90
0
e
−1
 204
Bi
83
This is ___positron emission_______________.
This is ___alpha decay______________.
This is ____electron capture____________.
This is ____alpha decay______________.
This is positron emission.
This is ____electron capture______________.
Radioactivity & Half-Lives
14. One of the radioactive nuclides formed in nuclear power plants is hydrogen-3, called tritium, which has a halflife of 12.26 years. How long before a sample decreases to 1/8 of its original amount?
1  ½  ¼  1/8
3 half lives x 12.26 = 36.78 years
15. Uranium-238 is one of the radioactive nuclides sometimes found in soil. It has a half-life of 454 years. What
percentage of a sample is left after 2270 years?
2270 / 454 = 4 half lives
100%  50  25  12.5  6.25%
16. Cesium-133, which is used in radiation therapy, has a half-life of 30 years. What was the size of the original
sample if after 120 years you now have 16.0 grams?
120/30 = 4 half lives
______  ____  _____  _____  16.0 grams
Work backwards!
256 grams
17. Phosphorus-32, which is used for leukemia therapy, has decayed to 1/16th of its original amount in 42.9 days.
What is the half-life of phosphorous-32?
1  ½  ¼  1/8  1/16
4 half lives
42.9/4 = 10.7 days
18. Iodine has a half-life of 8.07 days. Assuming you start with 90.5 grams, how much of the sample (in mg) would
you have left after 24.21 days?
24.21/8.07 = 3 half lives
90.5  45.25  22.625  11.3 grams
Bohr Model Diagrams
In the Bohr model diagrams show below, indicate the number of protons (p) and neutrons (n) in the nucleus of each atom.
Write the number of electrons (e) on each energy level. Not all energy levels will be used for every element.
19.
(a.)
silicon-30
Silicon has 4
valence e-
(b.)
calcium-41
8e4e-
P = 14
N = 16
Calcium has
2 valence e-
8e-
P = 20
N = 21
2e-
2e-
10e-
Electromagnetic Spectrum
20.
List the seven colors of the visible spectrum from shortest to longest wavelength.
violet, indigo, blue, green, yellow, orange, red
21.
What is the wavelength range of visible light? 400 nm to 700 nm.
22.
Draw your interpretation of a long wavelength (above the time frame) and a short wavelength (below the time
frame). Indicate which has higher frequency and higher energy.

23.
10 second time frame

(a) Which has a longer wavelength, orange or blue? orange
(b) Which has a lower frequency, green or red? red
(c) Which has more energy, indigo or yellow? indigo
Quantum Mechanics
Explain each of the following rules or terms associated with quantum mechanics.
24.
Hund’s Rule
electrons will avoid pairing if orbitals of equal energy are available, ex:
one electron in each p orbital before two.
25.
Aufbau Principle
electrons will fill orbitals from low to high energy
26.
Pauli Exclusion Principle
no two electrons can be in the same place at the same time, can’t have
the same four quantum numbers, ex: snowflakes
27.
Hesisenberg’s Uncertainty Principle
can’t know both the position and velocity of an electron, can only
estimate
28.
orbital
region of space that indicates the likelihood of where an e- might be: s
has 1, p has 3, d has 5, etc. Each orbital holds 2 electrons
29.
identify the four quantum numbers
energy level, sublevel-shape, which orbital within the sublevel, spin
Orbital Diagrams
Draw the orbital diagrams (boxes and arrows) for each of the following elements.
30.
silicon
31.
zinc
Electron Configuration
32.
Identify the element described by each electron configuration.
(a.)
1s22s22p63s2
magnesium (Mg)
(b.)
1s22s22p63s23p64s23d104p65s24d3
niobium (Nb)
(c.)
1s22s22p63s23p64s23d8
nickel (Ni)
(d.)
[Kr] 5s24d6
ruthenium (Ru)
(e.)
[Ar]4s23d104p4
selenium (Se)
Electron Configuration Continued
33.
34.
Write the full electron configuration for the following atoms/ions (do NOT use the Noble Gas shortcut method).
(a.)
P
1s22s22p63s23p3
(b.)
Y
1s22s22p63s23p64s23d104p65s24d1
(c.)
Ca+2
1s22s22p63s23p6
(d.)
Br-
1s22s22p63s23p64s23d104p6
Write the Noble Gas (shortcut) electron configuration for each of the following.
(a.)
Te
[Kr]5s24d105p4
(b.)
Sb
[Kr]5s24d105p3
(c.)
Bi
[Xe]6s24f145d106p3
Relating Bohr’s Diagram and Electron Configurations to the Quantum Numbers
35.
Which quantum number tells you the main energy level? n = principle quantum number = row in the periodic
table
46.
In the atom, 1s22s22p4 – what is the highest every level that holds an electron? 2
47.
How many orbitals are in the p-sublevel? 3 How many electrons? 6
48.
How many orbitals are in the d-sublevel? 5 How many electrons? 10
49.
Which quantum mechanical principle states that (choose from Pauli Exclusion Principle, Aufbau Principle, and
Hund’s Rule):
(a) electrons will fill orbitals from lowest to highest energy? Aufbau Principle
(b) no two electrons can have the same set of quantum numbers? Pauli exclusion principle
(c) electrons will avoid pairing in an orbital if an orbital of equal energy is available? (the sharing rule) Hund’s Rule
40.
How many electrons can be accommodated in each of the following:
(a) one d orbital 2
(b) a set of f orbitals 14
(d) the 7s orbital 2
(c) the n = 4 shell 32
(e) one p orbital 2
Important Vocabulary & Concepts to review
Define the following words
Trajectory
path followed by an electron
quantum
quantum world- small particles
quantum mechanics – math associated with electrons
quantum numbers – description of location of electron with highest energy in an atom
entail
include
valence electrons
electrons in the outermost shell, with highest energy, most likely to react
frequency
rate at which something occurs
Wavelength
distance between tops of a wave, red is the longest at 700nm, violet is the shortest at 400nm
Explain the following concepts (you can use words and pictures)
1. Nuclear decay
ANSWERS WILL VARY
2. Radioactivity
3. Radioactive particle
4. Half-Life
5. Fission
6. Fusion
7. Electron orbital diagram
8. Electron configuration
9. Bohr model of the atom
10. The relationship between wavelength, frequency and energy
11. The relationship between energy levels, sublevels and orbitals
12. The relationship between an element’s electron configuration & its position on the periodic table