Band of Stability

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-149 or Cs-139

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 nuclide(s) would you predict to be stable? Why?(a) 48K

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?

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.

Number of stable isotopes for elements 1-54.How many have an odd number of protons and more than two stable isotopes?

Which isotope in each pair is more stable? Why?(c) 2812Mg or  2412Mg

What is the most likely mode of decay for each nuclide?  (b) 120Xe

What is the most likely mode of decay for each nuclide?(a) 106In

The following nuclei do not lie in the band of stability. How would it be expected to decay?(d) 93 Li

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

The only stable isotope of fluorine is fluorine-19. Predict possible modes of decay for fluorine-21, fluorine-18, and fluorine-17.

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 in each pair would you expect to have the longer half-life?Cs-113 or Cs-125

Write a nuclear equation for the most likely mode of decay for each of the following unstable nuclides.Th-221

Predict the type of radioactive decay process for the following radionuclides.2968 Cu,

Which of the following isotopes would you expect to be stable?a. 208Pbb. Carbon-12c. Uranium 235d. 4Hee. 208Po

Determine whether or not the following nuclide is likely to be stable: Sn-102.

Observe the graph of the binding energy per nucleon shown to the right. Based on the graph, which of the following statements is true? A. One should expect that fusion type reactions that occur with nuclides with less than 56 nucleons should be exothermic.B. One should expect that fission type reactions that occur with nuclides with less than 56 nucleons should be exothermic.C. One should expect that fusion reactions that occur with nuclides with more than 56 nucleons should be exothermic.D. One should expect that fission reactions that occur with nuclides with more than 56 nucleons should be endothermic.  

Which isotope in each pair is more stable? Why?(d) 147N or 187N

Classify each nucleus as stable or unstable.a) 8942Mob) 11850Snc) 3015Pd) 21284Po

Which, of the following isotopes would you expect to be stable? a) uranium-238 b) 4He c) oxygen-16 d) 206Po e) 58Ni

Part B. In the PhET simulation under the Isotopes tab, click on the yellow cells corresponding to elements in the periodic table. Then, add or remove neutrons by dragging the gray particles either to the nucleus of the atom or to the bin beside the atom to obtain the specified isotope, determine which isotopes of the given elements are stable. Drag the appropriate items to their respective bins.Although every element contains a unique number of protons, there can be atoms of the same element that contain a different amount of neutrons. These different atoms of the same element are referred to as isotopes and differ in their atomic mass. Click on the image below to explore this simulation, building your own isotope of a selected element or making a mixture of isotopes. When you click this simulation link, you may be asked whether to run, open, or save the file. Choose to run or open itWhen the simulation is open you should the options to select Isotopes or Mixtures. Select Isotopes. You should see a scale with an atom of hydrogen on it. The current isotope (hydrogen-1) can be changed by adding neutrons from the bin located to the left of the scale. There is a periodic table in the upper right corner of the simulation showing cells in yellow representing the elements that can be selected. Clicking on the Mixtures tab at the bottom brings up a black background where custom isotope mixtures can be created or nature’s mix of isotopes can be viewed for a selected element.

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.)

Which nuclide is most likely to undergo beta decay?a) Si-22b) Rb-91c) Ar-35d) Co-52

Determine whether or not the following nuclide is likely to be stable: Ne-25.

In 2010, a team of scientists from Russia and the U.S. reported the 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]+ 301nIsotope 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?

Predict whether each nuclide is more likely to decay via beta decay or positron emission.(a) Pb-192(b) Pb-212(c) Xe-114

Write a nuclear equation for the most likely mode of decay for each of the following unstable nuclides.Kr-74

Which type of nuclear decay is the following radioactive isotope likely to undergo? a) beta decayb) alpha decayc) positron emission or electron captureHintAll known stable isotopes are shown on the graph. The points form what is know 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.

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

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.

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 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.21385Ata. beta decayb. alpha decayc. positron emission or electron capture

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.

Which of the following isotopes would you expect to be stable?a. uranium-238b. 4Hec. oxygen-16d. 208Poe. 58Ni