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Atoms and nuclear radiation key terms
Use these key terms for Atoms and nuclear radiation in AQA Physics 8463. The page is built from approved learning objectives for this topic and links back to the wider unit, topic hub, and related revision assets.
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key terms
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Topic
Atoms and nuclear radiation
Key terms
radioactive decay
The process in which an unstable nucleus emits radiation.
unstable nucleus
A nucleus that is not in a stable state and can emit radiation as it transforms to a more stable configuration.
radioactive decay
The process in which an unstable nucleus emits radiation.
random process
A process where the outcome cannot be predicted, such as the timing of radioactive decay.
radioactive decay
The process in which an unstable nucleus emits radiation, resulting in a change in the nucleus of an atom.
nucleus change
The alteration of an atomic nucleus due to the emission of radiation during radioactive decay.
alpha radiation
A type of nuclear radiation consisting of a helium nucleus, which contains two protons and two neutrons.
helium nucleus
The nucleus of a helium atom, made up of two protons and two neutrons, emitted during alpha radiation.
beta radiation
A type of radiation consisting of high-speed electrons emitted from the nucleus of an atom during radioactive decay.
nucleus
The central part of an atom, containing protons and neutrons, where nuclear reactions such as beta decay occur.
gamma radiation
Electromagnetic radiation emitted from the nucleus during radioactive decay.
nucleus
The central part of an atom, containing protons and neutrons.
neutron radiation
Neutron radiation consists of neutrons emitted from unstable nuclei during certain nuclear processes.
unstable nucleus
An unstable nucleus is one that can undergo radioactive decay, emitting radiation in the process.
alpha radiation
A type of nuclear radiation consisting of helium nuclei, which contain two protons and two neutrons.
gamma radiation
Electromagnetic radiation emitted from the nucleus of an atom, characterized by high penetration power and low ionizing ability.
alpha radiation
A type of nuclear radiation consisting of helium nuclei, which contains two protons and two neutrons, and is strongly ionising.
gamma radiation
A form of electromagnetic radiation emitted from the nucleus, which is weakly ionising but highly penetrating.
alpha radiation
A type of nuclear radiation consisting of helium nuclei, which contain two protons and two neutrons.
gamma radiation
A form of electromagnetic radiation emitted from the nucleus, characterized by high penetration power and low ionising ability.
alpha radiation
A type of nuclear radiation consisting of helium nuclei, which are strongly ionising but have low penetration ability.
ionising power
The ability of radiation to ionise atoms, with alpha radiation being highly ionising due to its charge and mass.
gamma radiation
Electromagnetic radiation emitted from the nucleus, characterized by weak ionising power and high penetration ability.
ionising power
The ability of radiation to remove electrons from atoms, leading to the formation of ions.
count rate
The number of counts detected each second or each minute from a radioactive source.
radioactive decay
The process in which an unstable nucleus emits radiation.
activity
The rate at which a sample of radioactive material decays, measured in becquerels (Bq).
becquerel
The unit of measurement for activity, defined as one decay per second.
Geiger-Muller tube
A device used to detect and measure ionizing radiation, including alpha, beta, and gamma radiation.
Ionizing radiation
Radiation that carries enough energy to liberate electrons from atoms or molecules, thereby ionizing them.
alpha decay
The process in which an unstable nucleus emits an alpha particle, consisting of two protons and two neutrons.
nuclear equation
A symbolic representation of a nuclear reaction, showing the initial and final nuclei, including any emitted particles.
beta decay
The process in which a beta particle, a high-speed electron, is emitted from an unstable nucleus.
nuclear equation
A symbolic representation of a nuclear reaction, showing the initial and final nuclei involved, including changes in mass and atomic numbers.
gamma emission
The release of electromagnetic radiation from the nucleus of an atom during radioactive decay.
nuclear equation
A symbolic representation of a nuclear reaction, showing the initial and final nuclei and any emitted particles.
mass number
The total number of protons and neutrons in the nucleus of an atom.
atomic number
The number of protons in the nucleus of an atom, which determines the element's identity.
nuclear equation
An equation that represents the changes in atomic and mass numbers during nuclear reactions.
atomic number
The number of protons in the nucleus of an atom, which determines the element's identity.
alpha decay
A type of radioactive decay in which an unstable nucleus emits an alpha particle, resulting in a decrease of mass number by 4 and atomic number by 2.
mass number
The total number of protons and neutrons in the nucleus of an atom, which determines the isotope of an element.
beta decay
A type of radioactive decay in which a high-speed electron is emitted from an unstable nucleus, resulting in an increase in atomic number by 1 while the mass number remains unchanged.
mass number
The total number of protons and neutrons in the nucleus of an atom, which remains unchanged during beta decay.
gamma emission
The release of electromagnetic radiation from the nucleus of an atom, which does not change the mass number or atomic number.
mass number
The total number of protons and neutrons in the nucleus of an atom, which is affected by nuclear reactions such as alpha and beta decay.
mass number
The total number of protons and neutrons in the nucleus of an atom.
atomic number
The number of protons in the nucleus of an atom, which determines the element's identity.
isotope notation
A way of representing isotopes of an element, showing the element's symbol, mass number, and atomic number.
nuclear equation
An equation that represents a nuclear reaction, balancing the mass numbers and atomic numbers of the reactants and products.
nuclear equation
An equation that represents the changes in atomic and mass numbers during nuclear reactions.
conservation of charge
The principle stating that the total electric charge before and after a nuclear reaction remains constant.
half-life
The time taken for the number of radioactive nuclei in a sample to halve.
radioactive decay
The process in which an unstable nucleus emits radiation.
half-life
The time taken for the count rate or activity from a source to fall to half its initial value.
count rate
The number of counts detected each second or each minute from a radioactive source.
radioactive decay
The process in which an unstable nucleus emits radiation.
half-life
The time taken for the number of radioactive nuclei in a sample to halve.
half-life
The time taken for the number of radioactive nuclei in a sample to halve.
radioactive decay
The process in which an unstable nucleus emits radiation.
half-life
The time taken for the number of radioactive nuclei in a sample to halve.
count rate
The number of counts detected each second or each minute from a radioactive source.
half-life
The time taken for the number of radioactive nuclei in a sample to halve.
decay graph
A graphical representation showing the change in count rate or activity of a radioactive substance over time.
half-life
The time taken for the number of radioactive nuclei in a sample to halve.
count rate
The number of counts detected each second or each minute from a radioactive source.
half-life
The time taken for the number of radioactive nuclei in a sample to halve.
activity
The rate at which a sample of radioactive material decays, measured in becquerels (Bq).
count rate
The number of counts detected each second or each minute from a radioactive source.
background count rate
The count rate from natural background radiation that must be subtracted from the measured count rate to obtain the true count rate from a source.
half-life
The time taken for the number of radioactive nuclei in a sample to halve.
decay curve
A graph showing the decrease in count rate or activity of a radioactive substance over time.
half-life
The time taken for the number of radioactive nuclei in a sample to halve.
activity
The rate at which a sample of radioactive material decays, measured in becquerels.
half-life
The time taken for the number of radioactive nuclei in a sample to halve.
decay graph
A graphical representation showing the change in count rate or activity of a radioactive substance over time.
radioactive contamination
the unwanted presence of radioactive atoms on or inside an object or person.
irradiation
exposure to ionising radiation from a radioactive source.
irradiation
exposure to ionising radiation from a radioactive source
ionising radiation
radiation that carries enough energy to free electrons from atoms or molecules, thereby ionising them
radioactive contamination
The unwanted presence of radioactive atoms on or inside an object or person.
irradiation
Exposure to ionising radiation from a radioactive source.
radioactive contamination
The unwanted presence of radioactive atoms on or inside an object or person.
irradiation
Exposure to ionising radiation from a radioactive source.
irradiation
Exposure to ionising radiation from a radioactive source.
radioactive contamination
The unwanted presence of radioactive atoms on or inside an object or person.
ionising radiation
Radiation that carries enough energy to liberate electrons from atoms or molecules, thereby damaging cells and DNA.
contamination
The unwanted presence of radioactive atoms on or inside an object or person, which can lead to exposure to ionising radiation.
ionising radiation
Radiation that carries enough energy to liberate electrons from atoms or molecules, potentially causing damage to biological tissues.
mutation
A change in the DNA sequence of an organism that can lead to alterations in its physical characteristics or functions.
alpha radiation
A type of nuclear radiation consisting of helium nuclei, which are made up of two protons and two neutrons.
gamma radiation
A form of electromagnetic radiation emitted from the nucleus, characterized by high penetration power and low ionising ability.
alpha radiation
A type of nuclear radiation consisting of helium nuclei, which contain two protons and two neutrons, emitted from an unstable nucleus.
gamma radiation
Electromagnetic radiation emitted from the nucleus of an atom during radioactive decay, characterized by its high penetration power and low ionizing ability.
alpha-emitting contamination
Radioactive contamination from alpha particles, which are highly ionising but have low penetration ability, making them particularly harmful when ingested or inhaled.
ionising radiation
Radiation that carries enough energy to liberate electrons from atoms or molecules, potentially causing damage to biological tissues and increasing cancer risk.
radioactive contamination
The unwanted presence of radioactive atoms on or inside an object or person.
irradiation
Exposure to ionising radiation from a radioactive source.
radioactive contamination
The unwanted presence of radioactive atoms on or inside an object or person.
irradiation
Exposure to ionising radiation from a radioactive source.
radiation risk
The potential harm to health from exposure to different types of radiation, influenced by factors such as radiation type, source location, activity, and half-life.
contamination
The unwanted presence of radioactive atoms on or inside an object or person, which can lead to radiation exposure.
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