Ch.19 - Nuclear ChemistryWorksheetSee all chapters
All Chapters
Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds

The Valley or Band of Stability represents the area where stable, non-radioactive isotopes exist based on their ratio of neutrons to protons. 

Valley of Stability 

Whenever the difference between neutrons to protons within a nucleus is significant enough an isotope is radioactive. 

Concept #1: The central idea of nuclear chemistry is that unstable nuclei will give off radiation. 

Neutrons act like the glue that keeps the nucleus together. The more neutrons present then the greater the attractive strong force, while the more protons then the greater the repulsive Coulombic force

Concept #2: Non-radioactive isotopes with the optimum number of neutrons to protons will lie within the Valley of Stability, while radioactive isotopes will lie outside of it. 

Example #1: Determine if the following nuclide will undergo alpha decay, beta decay or positron emission.

Hydrogen-3                                                                              

 

Example #2: Determine if the following nuclides will undergo alpha decay, beta decay or positron emission.

Radon-222

Example #3: Determine if the following nuclides will undergo alpha decay, beta decay or positron emission.

Magnesium-50

Additional Problems
Why does the band of stability curve upward at high atomic numbers? A. Excess neutrons are required due to the repulsion between the protons. B. If we have too many protons, not enough electrons will be orbiting the atom to keep it electrically neutral overall. C. Excess protons are required to help keep the neutrons from sticking together as neutrons have no charge. D. Atoms with high atomic numbers have a large number of electrons orbiting the nucleus. This increased number of electrons requires a lot of extra mass in the nucleus to keep the electrons in their orbit.
Which of the following nuclides is likely to lie above the band of stability? (a) 15O (b) 39C (c) 3He (d) 9Li (e) 13N
Which nuclide in each pair would you expect to have the longer half-life?Cs-113 or Cs-125
Which nuclide in each pair would you expect to have the longer half-life?Fe-62 or Fe-70
Which nuclide in each pair would you expect to have the longer half-life?Cs-149 or Cs-139
In 2010, a team of scientists from Russia and the U.S. reported creation of the first atom of element 117, which is not yet named and is denoted [117]. The synthesis involved the collision of a target of 97249Bk with accelerated ions of an isotope which we will denote Q. The product atom, which we will call Z, immediately releases neutrons and forms 117294[117]: 97249Bk + Q  →  Z  → 117294[117]+ 301n Isotope Q is unusual in that it is very long-lived (its half-life is on the order of 1019 yr) in spite of having an unfavorable neutron-to-proton ratio . Can you propose a reason for its unusual stability?
Stable and radioactive isotopes as a function of numbers of neutrons and protons in a nucleus.The stable nuclei (dark blue dots) define a region known as the belt of stability.Estimate the optimal number of neutrons for a nucleus containing 70 protons.
Determine whether or not the following nuclide is likely to be stable: Ne-25.
Determine whether or not the following nuclide is likely to be stable: Te-124.
Determine whether or not the following nuclide is likely to be stable: Ti-48.
Determine whether or not the following nuclide is likely to be stable: Cr-63.
Determine whether or not the following nuclide is likely to be stable: Sn-102.
Chlorine has two stable nuclides, 35Cl and 37Cl. In contrast, 36Cl is a radioactive nuclide that decays by beta emission.Based on the empirical rules about nuclear stability, explain why the nucleus of 36Cl is less stable than either 35Cl or 37Cl.
Predict a likely mode of decay for each of the following unstable nuclides.Ru-90
Predict the type of radioactive decay process for the following radionuclides.chlorine-39.
A radioisotope which is sometimes used by doctors to pinpoint a brain tumor is a. carbon-12 b. lead-206 c. technetium-99 d. uranium-238
Which radioisotope is used to treat thyroid disorders? a. Co-60 b. I-131 c. C-14 d. U-238
A radioactive isotope used in the study of many organic reaction mechanisms is a. carbon-12 b. carbon-14 c. oxygen-16 d. oxygen-18
Which of the following elements is stable? a. Carbon, atomic number 6 b. Boron, atomic number 5 c. Fluorine, atomic number 9 d. Neon, atomic number 10
Which type of nuclear decay is the following radioactive isotope likely to undergo?a. alpha decayb. beta decayc. positron emission or electron capture
Predict a likely mode of decay for the following unstable nuclide.Sb-132a. beta decay b. alpha decayc. positron emission
Predict a likely mode of decay for the following unstable nuclide.Te-139a. beta decay b. alpha decayc. positron emission
Predict a likely mode of decay for the following unstable nuclide.Ba-123a. beta decay b. alpha decayc. positron emission
Using general trends, predict the stability of the following nuclei. (stable or radioactive)a. Iron-56 b. sulfur-32 c. potassium-44 d. uranium-235 e. cobalt-58
Which of the following isotopes would you expect to be stable?i. carbon-12ii. 4Heiii. uranium-238iv. 58Niv. 208Po
Predict a likely mode of decay for each of the following unstable nuclides. Explain why. a. Mo-109 b. Fr- 202 c. Rn- 196 d. Sb - 132 e. P - 27 f. Ru - 90
Using general trends, predict the stability of the following nuclei as RADIOACTIVE or STABLE.1. arsenic-822. potassium- 443. radium- 2334. calcium- 405. zinc- 64
Which type of nuclear decay is the following radioactive isotope likely to undergo? All known stable isotopes are shown on the graph. The points form what is known as the "belt of stability". If a radioactive isotope is above the belt of stability, think about what type of decay would decrease its N/Z ratio. If an unstable isotope is below the belt of stability, think about what type of decay would increase its N/Z ratio. If a radioactive isotope is off the chart (Z > 83), think about what type of decay would decrease Z the most. a. beta decay b. alpha decay c. positron emission or electron capture
Which of the following isotopes would you expect to be stable?a. 208Pbb. Carbon-12c. Uranium 235d. 4Hee. 208Po
Which nuclide(s) would you predict to be stable? Why?  (a) 820O
Which nuclide(s) would you predict to be stable? Why?(a) 14660Nd
Which nuclide(s) would you predict to be stable? Why?(c)  8842Mo
Which nuclide(s) would you predict to be stable? Why?(a) 14660Nd
You may want to reference (Pages 906 - 909)Section 21.2 while completing this problem.One of the nuclides in each of the following pairs is radioactive. Predict which is radioactive and which is stable.(a) 3919K and 4019K
Which of the following nuclides would you expect to be radioactive: 2658Fe, 2760Co, 4192Nb, mercury-202, radium-226?
Which nuclide(s) would you predict to be stable? Why?   (a) 127I
Which nuclide(s) would you predict to be stable? Why?(a) 48K
Which nuclide(s) would you predict to be stable? Why?(b) 79Br
In the sketch below, the red spheres represent protons and the gray spheres represent neutrons.Based on its atomic number and mass number, do you think the product nucleus is stable or radioactive?
Determine whether or not each of the following nuclides is likely to be stable:a. Ti-48          b. Cr-63          c. Sn-102          d. Y-88
Identify the best reason to explain the stability for each isotope.a. Ti-48          b. Cr-63          c. Sn-102          d. Y-88
Indicate whether each of the following nuclides lies within the belt of stability in Figure 21.2 in the textbook.(a) neon-24,(b) chlorine-32, (c) tin-108, (d) polonium-216. For any that do not, describe a nuclear decay process that would alter the neutron-to-proton ratio in the direction of increased stability.
Which of the following nuclides have magic numbers of both protons and neutrons?(a) helium-4(b) oxygen-18(c) calcium-40(d) zinc-66(e) lead-208
Number of stable isotopes for elements 1-54.How many have an odd number of protons and more than two stable isotopes?
You may want to reference(Pages 905 - 909)Section 21.2 while completing this problem.One nuclide in each of these pairs is radioactive. Predict which is radioactive and which is stable. Explain your choice in each case.(a) 4020Ca and 4520Ca,
Which isotope in each pair is more stable? Why?(a) 14055Cs or 13355Cs
Which isotope in each pair is more stable? Why?(b) 7935Br or 7835Br
Which isotope in each pair is more stable? Why?(c) 2812Mg or  2412Mg
Which isotope in each pair is more stable? Why?(d) 147N or 187N
Nuclei differ in their stability, and some are so unstable that they undergo radioactive decay. The ratio of the number of neutrons to number of protons (N/Z) in a nucleus correlates with its stability. Calculate the N/Z ratio for (b) 56Fe
All the stable isotopes of boron, carbon, nitrogen, oxygen, and fluorine are shown in the chart in the right hand column (in red), along with their radioactive isotopes with t1/2 > 1 min (in blue).Write the chemical symbols, including mass and atomic numbers, for all of the stable isotopes.
Which of the following nuclei is most likely to decay by positron emission? Explain your choice.(a) chromium-53(b) manganese-51(c) iron-59
The following nuclei do not lie in the band of stability. How would they be expected to decay? Explain your answer.(b) 23992 U
The following nuclei do not lie in the band of stability. How would they be expected to decay? Explain your answer.(c) 3820 Ca
The following nuclei do not lie in the band of stability. How would they be expected to decay? Explain your answer.(e) 24594 Pu
What is the most likely mode of decay for each nuclide?(a) 11147Ag
What is the most likely mode of decay for each nuclide?(c) 11044Ru
What is the most likely mode of decay for each nuclide?   (a) 15C
What is the most likely mode of decay for each nuclide?  (b) 120Xe
What is the most likely mode of decay for each nuclide?  (c) 224Th
What is the most likely mode of decay for each nuclide?(a) 106In
Representations of three nuclei (with neutrons gray and protons purple) are shown below. Nucleus 1 is stable, but 2 and 3 are not. (b) What is (are) the most likely mode(s) of decay for 2 and 3?
The following nuclei do not lie in the band of stability. How would it be expected to decay?(a) 2815 P
Predict whether each nuclide is more likely to decay via beta decay or positron emission.(a) Pb-192(b) Pb-212(c) Xe-114
The following nuclei do not lie in the band of stability. How would it be expected to decay?(b) 23592 U
The following nuclei do not lie in the band of stability. How would it be expected to decay?(d) 93 Li
The following nuclei do not lie in the band of stability. How would it be expected to decay?(e) 24596 Cm
Predict by what mode(s) of spontaneous radioactive decay the following unstable isotope might proceed:(a) 62 He
Predict by what mode(s) of spontaneous radioactive decay the following unstable isotope might proceed:(b) 6030 Zn
There are four stable isotopes of iron with mass numbers 54, 56, 57, and 58. There are also two radioactive isotopes: iron-53 and iron-59. Predict modes of decay for these two isotopes. (See in the following table.)
The only stable isotope of fluorine is fluorine-19. Predict possible modes of decay for fluorine-21, fluorine-18, and fluorine-17.
You may want to reference (Pages 906 - 909)Section 21.2 while completing this problem.Each of the following nuclei undergoes either beta or positron emission. Predict the type of emission for each.(a) tritium, 31H
Predict whether the following nuclide is stable or unstable (radioactive). If the nuclide is unstable, predict the type of radioactivity you would expect it to exhibit.c. 2011Na
Which nuclide is most likely to undergo beta decay?a) Si-22b) Rb-91c) Ar-35d) Co-52
Predict the type of radioactive decay process for the following radionuclides.2968 Cu,
Using general tendencies, predict the most likely mode of decay of each of the following radioactive isotopes.( α decay , β decay, e emission, e capture)1. iodine-1372. sodium - 203. thorium- 2324. mercury- 1905. potassium- 47
Nuclei above the belt of stability can lower their neutron-to-proton ratio through whichprocess?A. alpha decayB. beta emissionC. gamma emissionD. positron emissionE. electron capture
Which of the following isotopes would you expect to be stable?a. uranium-238b. 4Hec. oxygen-16d. 208Poe. 58Ni