P6.1 radioactive emissions Flashcards
why do some atoms of the same elements have the same charge but different masses
isotopes, due to different numbers of neutrons as they have a charge of 0 but a mass of 1 relative to a proton
what happens to most isotopes
they are unstable, meaning they produce radioactive emissions to become more stable
what are the 4 different types of radioactive emissions / decay
alpha, beta, gamma and a neutron
what is an alpha particle
an alpha particle consists of 2 protons and 2 neutrons, the same as a helium nucleus. there are no electrons in a nuclei so the charge is 2+
what is a beta particle
the beta particle is a fast-moving electron
how is a beta particle formed and why
radiation occurs in the nucleus and since nuclei do not contain electrons, a neutron is split into a proton and fast moving electron to make the nucleus more stable
what is a geiger counter and how does it work
a geiger counter measures the amount of radiation that occurs by producing a clicking sound every time radiation occurs in it. Each click is made from a tiny current that is produced when the radiation ionises atoms of gas inside.
what are the properties of an alpha particle
highly ionising , low penetrating power
what are the properties of beta particles
moderately ionising and moderately penetrating ( can be stopped by a few m of aluminium)
what are the properties of gamma rays
low ionising but highly penetrating (can be stopped by a few cm of lead but some may still pass through this)
what happens when an atom is ionised?
the particle transfers energy to ionise the atom which causes the atom to lose an electron and turn into positively charged ions.
what is half life
the time taken for the number of radioactive nuclei to halve or the time taken for the acitvity (rate of decays) to halve
what is activity measured in?
bequerels
is the decay process random or constant
random
is the activity (rate of decay) random or constant
constant
