Atomic Structure and Interactions Cognitive Enabling Objectives

Which of the following statements are true when describing a proton?

• Mass~1AMU

• Is a Nucleon

• Has positive charge

Which of the following statements are true when describing a neutron?

• Mass of ~1 AMU

• Is a nucleon

• No charge

Which of the following statements are true when describing an electron?

• Mass of ~1/1832 AMU

• Negative charge

Which of the following criteria are true when describing the isotope 131^I_53

• 131 Nucleons

• 78 Neutrons

• 53 protons

How many neutrons are in the nucleus of 137^CS_55

82 neutrons

What is the term for two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei?

Isotopes

Which of the following statements are true when describing mass defect and binding energy?

• Mass of nucleus is less than the summed mass of individual nucleons.

• Mass defect is converted into energy which binds the protons and neutrons in the nucleus.

Which of the following statements are true when describing alpha decay?

• Occurs with large isotopes with an atomic number>88 and mass>210

• Alpha particle has a +2 charge and a mass of 4 AMU.

• Decays with a discrete energy (monochromic energy)

Which of the following statements are true when describing beta decay?

• Decays with spectrum energy

• Neutron becomes a proton and emits a beta particle.

Which of the following statements are true when describing positron decay?

• Mass of ~1/1832 AMU

• Proton becomes a neutron and emits a positron

Drag each equation on the right to the type of decay that it describes on the left.

How many half-lives must elapse for the activity of a nuclide to reach 1/8 of the initial activity?

3

Which of the following statements are true when describing the Chart of the Nuclides?

• Protons are plotted along the vertical axis

• A black triangle in the lower right hand corner of the square indicates a fission product of U-235

• A gray square indicates stable isotopes or isotopes with a half-life greater than 5.0 E +8 years.

What is the term used to describe when a low energy gamma interacts with an electron and all of the photon energy is imparted to the electron in the form of kinetic energy?

Photoelectric effect

What is the term used to describe when a gamma interacts with an electron and only imparts a portion of its energy to the electron, reducing the energy of the gamma and also changing its direction?

Compton scattering

What is the term used to describe when a high che photon energy is converted to a beta particie and a positron with kinetic energy?

Pair production

What is the minimum energy of a photon for pair production to occur?

1.022 MeV

What is the term for when a neutron strikes a small nucleus and no energy is transferred to excite the target nucleus.

Elastic scatter

What term is used to average the number of ion pairs produced by a charged particle per unit length of travel.

Specific ionization

What is the term used to describe when a photon strikes an electron but the electron does not have enough energy to escape from the atom?

Excitation

____ ionization refers to the ion pairs produced by an electron that has been ejected from an atom due to a radiation interaction.

Secondary

A typical ___ particle has a range of approximately 1 to 2 inches in air.

Alpha

A typical ___ particle has a range of approximately 0.5 cm in tissue or water.

Beta

What is the term for when a neutron strikes a large nucleus and transfers some of its kinetic energy to the excitation of the nucleus.

Inelastic scatter

Which of the following isotopes are activated corrosion products?

• Co-58

• Co-60

• Mn-56

Which of the following isotopes are produced by the activation of impurities in reactor coolant?

• Ar-41

• H-3

• Na-24

Which of the following isotopes are produced by the activation of water?

• F-18

• N-16

Which of the following statements describe nuclear fission?

• Each fission of U-235 releases ~200 MeV of energy.

• Fission occurs when the nucleus reaches a critical energy•

• U-235 is fissile.

• Fission produces 2 fission fragments of unequal size.

Check all of the actions that can decrease the Minimum Detectable Activity (MDA).

• Increase sample volume.

• Move the counter to an area with a lower background.

• Increase sample count time.

• Use an instrument with a higher detection efficiency.