P3 Further Additional Topic 3

Frage	Antworten
Describe the properties of alpha radiation.	Made up of two protons and two neutrons (helium nucleus). They have a charge of +2 and a mass of 4.
Describe the properties of beta radiation.	They are high energy electrons. They have a negative (-1) charge.
Describe the properties of gamma radiation.	They are high frequency electromagnetic radiation. They do not have a charge.
Describe the properties of neutron radiation.	They are uncharged particles.
Describe the properties of positron and radiation.	They are positively (+1) charge particles. They have the same mass of an electron.
Recall the relative masses and relative electric charges of protons, neutrons, electrons and positrons.	Proton: charge +1, mass 1 Neutron: charge 0, mass 1 Electron: charge -1, mass 1/2000 Positron: charge +1, mass 1/2000
Recall which particles in an atom are found in equal numbers.	In an atom the number of protons equals the number of electrons.
Describe the process of β- decay.	A neutron becomes a proton and emits an electron.
Describe the process of β+ decay.	A proton becomes a neutron and emits a positron.
Explain the effects on the atomic (proton) number and mass (nucleon) number of α, decay.	The atomic number decreases by 2 and the mass number decreases by 4 because 2 protons and 2 neutrons (helium nucleus) are lost.
Explain the effects on the atomic (proton) number and mass (nucleon) number of β- decay.	The atomic number increase by 1 and the mass number stays the same because a neutron has turned into a proton.
Explain the effects on the atomic (proton) number and mass (nucleon) number of γ decay.	The atomic number and the mass number stay the same because no mass or charge has been lost.
Describe the features of the N-Z curve for stable isotopes.	Stable isotopes lie on the stability curve. Isotopes that do not lie on this curve are unstable. For isotopes with a proton number (Z) = 20 or below, the number of protons = the number of neutrons (N).
Recall which decay nuclei with high values of Z (above 82) usually undergo.	Nuclei with high values of Z (above 82) usually undergo alpha decay.
Recall which decay an isotope above the stability curve will undergo.	An isotope above the stability curve will undergo (β-) decay.
Explain why an isotope above the stability curve will undergo (β-) decay.	An isotope above the stability curve will undergo (β-) decay because it has too many neutrons.
Recall which decay an isotope below the stability curve will undergo.	An isotope below the stability curve will undergo (β+) decay.
Explain why an isotope below the stability curve will undergo (β+) decay.	An isotope below the stability curve will undergo (β+) decay because it has too few neutrons (too many protons).
Recall what protons and neutrons contain.	Protons and neutrons contain 3 quarks each.
Describe the arrangement of quarks in protons and neutrons.	Protons: Up, up, down. Neutrons: Up, down, down.
Explain, through calculation, the arrangement of up and down quarks in protons in terms of charge and mass.	Quarks: Up, up, down. Charge: + 2/3 + 2/3 -1/3 = 1 Mass: 1/3 + 1/3 +1/3 = 1
Explain, through calculation, the arrangement of up and down quarks in neutrons in terms of charge and mass.	Quarks: Up, down, down. Charge: + 2/3 - 1/3 -1/3 = 0 Mass: 1/3 + 1/3 +1/3 = 1
Explain (β-) decay as a process that involves quarks.	A neutron becomes a proton because a down quark is changing into an up quark. u, d, d --> u, u, d
Explain (β+) decay as a process that involves quarks.	A proton becomes a neutron because a up quark is changing into an down quark. u, u, d --> u, d, d
Recall what is released from nuclei that have undergone radioactive decay.	Nuclei that have undergone radioactive decay lose energy as gamma radiation.
Explain why gamma radiation is released from nuclei that have undergone radioactive decay.	Nuclei that have undergone radioactive decay lose energy as gamma radiation because they often undergo nuclear rearrangement.
Describe the dangers of ionising radiation.	The dangers of ionising radiation are tissue damage and possible mutations of DNA and cells, leading to cancerous tumours.
Explain the precautions taken to ensure the safety of people exposed to radiation.	the precautions taken include limiting the dose and exposure time for patients and increasing distance and using lead walls/aprons for medical personnel These will decrease the intensity of the radiation.
Compare and contrast the treatment of tumours using radiation applied internally or externally.	Internal radiotherapy: Radioactive source placed inside the body, must be injected or implanted, damage to surrounding tissue is limited. External radiotherapy: Treatment is shorter, only lasts a few minutes, some short an long term effects.
Describe palliative care including the use of radiation in some instances.	Palliative care is given to patients when the cancer is incurable. It prolongs life and eases pain and symptoms by reduce the size of the tumour. This improves the patients quality of life.
Explain the use of radioactive substances as tracers in diagnosis of medical conditions.	Radioactive isotopes (e.g. iodide-131) are used as traces. The tracer is swallowed or injected and then absorbed by cancerous tissue. An image is created where the reading of radiation is strongest.
Explain the use of radioactive substances in PET scanners in diagnosis of medical conditions.	Radioactive isotopes (e.g. fluorine-18) are used as traces. The tracer is swallowed or injected and then absorbed by cancerous tissue. The tracer emits positrons that annihilate with electrons. This produces high-energy gamma rays which can be detected.
Explain why isotopes used in PET scanners have to be produced nearby.	Isotopes used in PET scanners have to be produced nearby because they have short half-lives.

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P3 Further Additional Topic 3

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