Types of Radiation and Radioactivity CH2
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Questions and Answers

What is the primary hazard of beta particles?

  • External exposure
  • Ingestion
  • Direct skin contact
  • Inhalation (correct)

Which type of isotopes are radioactive and emit radiation?

  • Stable isotopes
  • Radioisotopes (correct)
  • Artificial isotopes
  • Noble gases

How can gamma rays be best described?

  • Fast-moving electrons
  • Charged particles with mass
  • Neutrons with energy
  • High-energy photons with no mass (correct)

Which decay mode involves a heavy nucleus splitting into two fragments?

<p>Spontaneous fission (C)</p> Signup and view all the answers

What do stable isotopes have in common?

<p>They occur naturally and are not radioactive (D)</p> Signup and view all the answers

Which particle has no charge and the same mass as a proton?

<p>Neutron (D)</p> Signup and view all the answers

Which of the following processes is least probable in uranium-238?

<p>Spontaneous fission (C)</p> Signup and view all the answers

What distinguishes metastable nuclei from other nuclei?

<p>They release only gamma radiation (D)</p> Signup and view all the answers

What happens to the atomic number of an atom during alpha decay?

<p>It decreases by 2 (B)</p> Signup and view all the answers

Which type of decay occurs when there are too many neutrons in an atom?

<p>Beta decay (B)</p> Signup and view all the answers

What is emitted during beta plus (β+) decay?

<p>Neutrino (B)</p> Signup and view all the answers

What does the mass number of an atom do during alpha decay?

<p>It decreases by 4 (A)</p> Signup and view all the answers

What contributes to the energy difference between parent and daughter nuclides in beta decay?

<p>Transition or decay energy (D)</p> Signup and view all the answers

How is the range of alpha particles in matter described?

<p>Very short (C)</p> Signup and view all the answers

What is the consequence of a neutron converting into a proton during beta decay?

<p>Atomic number increases by one (B)</p> Signup and view all the answers

What defines an atom as ionized?

<p>It has gained or lost electrons. (B)</p> Signup and view all the answers

What is required for positron decay to occur?

<p>Energy difference greater than 1.02 MeV (B)</p> Signup and view all the answers

Which particles constitute an alpha particle?

<p>2 protons and 2 neutrons (C)</p> Signup and view all the answers

Which type of radiation is capable of removing electrons from atoms?

<p>Ionizing radiation (A)</p> Signup and view all the answers

What is a characteristic of isotopes?

<p>They have the same number of neutrons. (A)</p> Signup and view all the answers

What are isobars?

<p>Atoms with different numbers of protons and neutrons but the same total nucleons (A)</p> Signup and view all the answers

What type of radiation includes visible light and microwaves?

<p>Non-ionizing radiation (C)</p> Signup and view all the answers

How does technetium-99m decay?

<p>By emitting a gamma ray (D)</p> Signup and view all the answers

Which of the following statements about isotones is true?

<p>They have different numbers of protons but the same difference in nucleon count. (B)</p> Signup and view all the answers

What is produced when a positron combines with an atomic electron?

<p>Photons of 511 keV (B)</p> Signup and view all the answers

What happens to the atomic number of the daughter nuclide during electron capture?

<p>It decreases by 1 (B)</p> Signup and view all the answers

In which cases can both electron capture and positron decay occur?

<p>When excitation energy is greater than 1.02 MeV (C)</p> Signup and view all the answers

Which equation represents the relationship between activity, decay constant, and the number of radioactive atoms?

<p>A = λN (B)</p> Signup and view all the answers

What does the decay constant (λ) represent in radioactive decay equations?

<p>The rate of decay (D)</p> Signup and view all the answers

What is the equation to calculate the half-life (T1/2) in terms of the decay constant (λ)?

<p>T1/2 = 0.693/λ (D)</p> Signup and view all the answers

What does the average (mean) lifetime (Ƭ) represent for radioactive atoms?

<p>The average time for all atoms to decay (A)</p> Signup and view all the answers

What defines the effective half-life (Te) of a radiopharmaceutical?

<p>Time for half of the material to be eliminated from the biological system (B)</p> Signup and view all the answers

Flashcards

Ionizing Radiation

Radiation with enough energy to remove electrons from atoms or molecules.

Non-ionizing Radiation

Radiation without enough energy to remove electrons from atoms or molecules.

Alpha Particle

A type of particulate radiation consisting of 2 protons and 2 neutrons.

Isotopes

Atoms with the same number of protons but different numbers of neutrons.

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Isobars

Atoms with a different number of protons and neutrons, but same total number of nucleons (protons + neutrons).

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Isotones

Atoms with the same number of neutrons but different numbers of protons (and therefore different atomic numbers).

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Radioactive Decay

The process where an unstable atomic nucleus transforms into a more stable one by emitting radiation.

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Gamma Ray

A type of electromagnetic radiation emitted during some radioactive decay transitions. It carry high energy.

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Beta Particles

Fast electrons or positrons with a ±1 charge, equal mass to electrons. Stopped by clothing.

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Neutrons

Particles with no charge and the same mass as protons, behave like bowling balls, stopped by a layer of clothing.

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Radioisotopes

Radioactive isotopes that emit radiation.

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Spontaneous Fission

A heavy nucleus breaking into two fragments with the emission of neutrons. Low probability.

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Radionuclides

Unstable nuclei decaying by emitting particles or gamma radiation to become stable.

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Half-life

The time it takes for half of a radioactive substance to decay.

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Positron Decay

A type of radioactive decay where a proton in the nucleus converts into a neutron, emitting a positron and a neutrino.

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Electron Capture (EC)

A type of radioactive decay where an inner-shell electron is absorbed by a proton in the nucleus, forming a neutron and a neutrino.

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Radioactive Decay Equation

A = A₀e⁻¹⁰t describes the decrease in activity (A) over time.

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Half-life (T₁/₂)

The time required for half of the radioactive nuclei to decay.

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Decay Constant (λ)

A constant that describes the rate of radioactive decay.

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Effective Half-Life (Tₑ)

The time needed for half the radiopharmaceutical to leave the body.

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Average Life Time (τ)

The average time for a radioactive atom to decay

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Alpha decay

A type of radioactive decay in which an atomic nucleus emits an alpha particle and transforms into a different nucleus with a mass number 4 less and atomic number 2 less.

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Beta decay

A type of radioactive decay in which a neutron transforms into a proton, releasing a beta particle (electron) and an antineutrino.

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Mass number

The total number of protons and neutrons in an atom's nucleus.

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Atomic number

The number of protons in an atom's nucleus.

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Study Notes

Types of Radiation and Radioactivity

  •  Radiation is classified as ionizing or non-ionizing, based on its ability to ionize matter
  •  Ionizing radiation possesses enough energy to remove an electron from an atom or molecule
  •  Non-ionizing radiation lacks the energy to separate molecules or remove electrons
  •  Types of ionizing radiation include particulate (alpha, beta, and neutron) and electromagnetic (gamma rays)
  •  Alpha particles are helium nuclei (2 neutrons and 2 protons), positively charged, and have low penetration power (stopped by paper)
  •  Beta particles are high-speed electrons or positrons; they are negatively or positively charged and have moderate penetration power (stopped by a few millimeters of material)
  •  Neutrons have no charge and the same mass as protons; they have high penetration power
  •  Gamma rays are electromagnetic radiation with no charge and no mass; high penetration power (stopped by thick lead or concrete)
  •  Radioactive decay processes allow unstable atomic nuclei to reach a stable configuration. These processes include alpha, beta, and electron capture
  •  A radionuclide decays to a more stable configuration via various modes, including spontaneous fission; isomeric transition; alpha, beta, positron decay; and electron capture
  •  Spontaneous fission occurs in heavy nuclei that break into smaller nuclei
  •  Alpha decay decreases atomic number by two and mass number by four
  •  Beta decay converts a neutron into a proton, increasing the atomic number by one
  •  Electron capture combines an inner-shell electron with a proton, lowering the atomic number by one
  •  The difference in energy between the parent and daughter nuclides is called the transition or decay energy
  •  The half-life (T1/2) is the time needed for half of the radioactive nuclei to decay, calculated as 0.693/λ (decay constant)

Isotopes

  •  Isotopes of a given element contain the same number of protons but varying numbers of neutrons
  •  Most elements have more than one stable isotope
  •  Stable isotopes are non-radioactive and occur naturally
  •  Radioisotopes are radioactive and emit radiation. Some are natural, and others are artificially created

Isobars

  • Isobars are atoms with different numbers of protons and different numbers of neutrons, but the same total number of nucleons.

Isotones

  • Isotones are atoms with different atomic numbers and different mass numbers with constant (A-Z) value; they contain the same number of neutrons.

Isomers

  •  Isomers are identical atoms, but they exist at different energy states due to differences in nucleon arrangements
  •  Technetium-99m decays to technetium-99, with the emission of a 140-keV gamma ray, useful in nuclear medicine

Radioactive Decay Laws

  •  Radioactive decay is the process by which an unstable nucleus loses energy by emitting radiation. A material holding unstable nuclei is radioactive.

  •  The radioactive decay described by A = A₀e⁻ -λt. Where: -A is the activity present after time t. -A₀ is the initial activity at time equals zero. -λ is the decay constant in time. -t is the time taken to change activity from A to A.

  • Mean life time T=1/λ

  • T1/2= 0.693/λ

  • Units of radioactivity: Curie (Ci) = 3.7 × 10¹⁰ disintegrations/sec, and Becquerel (Bq) = 1 disintegration/sec.

  • 1 Ci = 3.7 x 1010 Bq

  • The concept of half-life is essential for radiologic science. It's used in nuclear medicine and x-ray terminology, with the half-value layer as a parallel component. 3.3 half-lives equal 1/10 life.

  • In any biologic system, the loss of a radiopharmaceutical is due to two factors: physical decay of the radionuclide and biological elimination of the radiopharmaceutical. The effective rate (λe) of loss is related to λp (physical rate) and λb (biological rate).

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Types of Radiation and Radioactivity Lecture Notes PDF

Description

This quiz explores the different types of radiation, including ionizing and non-ionizing forms. Learn about alpha, beta, and gamma radiation, their characteristics, and their penetration abilities. Test your knowledge on radioactivity and its implications in various contexts.

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