P6 Flashcards
what is the nucleus comprised of
protons and neutrons
what is the relative charge of a proton, neutron, and electron
proton: +1
neutron: 0
electron: -1
what is the proton number
the number of protons in the nucleus of an atom
what is the nucleon number
the total number of protons and neutrons present in the nucleus of an atom
how do you calculate the number of neutrons in an atom
nucleon number - proton number
what is an isotope
atoms with the same number of protons but different number of neutrons
what is background radiation
the radiation that exists around us all the time
what are some sources of background radiation
radon gas (in the air), rocks and buildings, food and drinks, cosmic rays
what is ionising nuclear radiation
radiation that has enough energy to remove electrons from the orbit of an atom, causing that atom to become ionised
what is radioactive decay
a change in an unstable nucleus that can result in the emission of α-particles, β-particles, or γ-rays (to lose energy). these changes are spontaneous and random
what is the nature of α-particles
2 protons, 2 neutrons
what is the nature of β-particles
high energy, high speed electrons
what is the nature of γ-rays
extremely high energy photon
what is the nuclide notation of α, β, γ
what are the relative ionising abilities of α, β, γ emissions and why
α- most ionising (most massive, most charge)
β- medium ionising (middle mass, middle charge)
γ- least ionising (no mass, no charge)
what are the relative penetrative abilities of α, β, γ emissions
α- least penetrating (as most ionising)
β- medium (medium ionising)
γ- most (least ionising)
material required to stop each form of ionising radiation
α- paper
β- several mm of aluminium
γ- several cm of lead/metres of concrete
what are some safety measures when handling ionising radiation
- limit exposure time
- shielding: place barrier in between you and radiation
- increase distance to reduce intensity
what is the nuclear decay equation for alpha decay
what is the nuclear decay equation for beta decay
what is the nuclear decay equation for gamma decay
what are some of the applications of ionising radiation
- household fire (smoke) alarms (α)
- irradiating food to kill bacteria (γ)
- sterilisation of equipment (γ)
- measuring and controlling thicknesses of materials (β, γ)
- diagnosis and treatment of cancer (γ)
how is ionising radiation measured
using a Geiger-Müller (GM) tube connected to a counter
what is count rate measured in
counts / second, counts / minute
what is half-life
the time taken for the number of unstable nuclei of a particular isotope to halve
what is nuclear fusion and where does it occur
when two nuclei join and energy is released. it occurs in the Sun’s core
what is nuclear fission and where does it occur
when a nuclei split into daughter nuclei, releasing energy. it occurs in nuclear reactors
