P5 - Radioactive Materials Flashcards
what is the atomic number?
the number of protons
what is the mass number?
the number of protons and neutrons
what are isotopes?
are atoms that have the same number of protons as each other but a different number of neutrons
what is radioactive decay?
nuclei of unstable isotopes tend to decay into other elements and give out radiation as they try become more stable
what makes a substance radioactive?
it contains unstable isotopes
what is ionising radiation?
radiation that knocks electrons off atoms, creating positive ions
alpha particle
2 neurons
2 protons
essentially helium (He)
beta particle
identical to an electron
relative charge of -1
for every beta particle emitted, a neutron turns into a proton in the nucleus
gamma ray
no mass, no charge
neutron emission
neutron is thrown out
just becomes an isotope
atomic number doesn’t change
what has the lowest and highest ionising power ranked
gamma
beta
alpha
what is 1Bq?
one decay per second
what does half-life mean?
the time taken for a number of radioactive nuclei in a sample to halve
true or false: as the number of unstable particles decrease in a sample, the overall rate of decay also decreases
true
What does a lower dose of ionising radiation do to your cells?
damage living cells by causing mutations in DNA. This can cause the cell to divide uncontrollably - which is cancer
What does a higher dose of ionising radiation do to your cells?q
tend to kill cells completely, which can cause radiation sickness if a lot of cells all get blasted at once.
if radiation from a radioactive source reaches your body, you are being??
irradiated
ways to reduce irradiation
- standing far from the source
- not to point sources directly at people
- store them in lead-lined boxes when not in use
if a radioactive source ends up on or inside your body, your body is??
contaminated
what type of radiation is the most dangerous outside the body?
beta and gamma
beta particles and gamma rays can both penetrate the body and get to delicate organs. Gamma rays sin embargo can penetrate even further
alpha particles on penetration
can’t penetrate the skin
inside the body they’re the most dangerous as they do all their damage in a very localised area
What are used as tracers?
certain radioactive isotopes that emit gamma radiation are used as tracers
why do tracers have to have a short half-life?
so the source becomes relatively safe quite quickly, but long enough that is still emits radiation.
