Chapter 25 ReviewSolutions

Which of the following particles cannot be stopped by metal foil?

a. Alpha b. Beta c. Gamma

Which particle of radiation carries the greatest amount of energy?

a. Alpha b. Beta c. Gamma

Which particle in the following nuclear reaction is the parent nuclide?

HeNanAl 42

2411

10

2713

True or False. All nuclear decay reactions are considered transmutation reactions.

Which element is used in a nuclear fusion reactor? Hydrogen or Uranium

Which variable(s) must be conserved in a nuclear reaction?

Mass numberThe number of protonsThe number of neutronsThe atomic numberThe type of atoms

Which nuclear process is more likely to occur when the mass number is over 60? Fission or Fusion

When is positron emission most effective? the neutron to proton ratio is above the band of stability

the neutron to proton ratio is below the band of stability

When is alpha decay most effective? the neutron to proton ratio is above the band of stability

the neutron to proton ratio is below the band of stability

When is electron capture most effective? When there is an excess of protons

When there is an excess of neutrons

What changes in a nuclear equation when a nucleus undergoes beta decay? (choose all)

A. Mass number B. Atomic number C. the number of neutrons

What is a positron?

A positron is a particle that has the mass of a beta particle and a charge of +1

What is required to sustain a chain reaction?

a. High temperature b. Critical mass c. Water

Is Calcium-45 a stable isotope of calcium? Yes or No If your answer is no, what type of decay would it undergo

Beta

Sodium-20 is an unstable isotope of sodium. What two types of decay might it undergo?

Electron capture or positron emission

Above what atomic number do most unstable atoms undergo alpha decay?

83

Write the induced transmutation reaction for the alpha bombardment of Thorium 230 which produces two neutrons, a beta particle and another nuclide.

h𝑇 + 𝐻𝑒→2 𝑛+ 𝛽+ 𝑁𝑝93232

−10

01

24

90230

If the half-life of a radioactive isotope is 12 minutes and 1 hour and 36 minutes passes, how many half-lives have taken place?What fraction of the sample will remain after that time?

1/256

If a radioactive isotope decays from 16g to 2g in 15 days, what is the isotope’s half-life?

5 Days

How much of a 20g sample of Zn-65 will remain after 18 years if the half- life of Zn-65 is 6 years?

2.5g

What is the daughter nuclide in the following reaction?

nCmHePu 10

24296

42

23994