Radioactivity Flashcards
What are radioisotopes?
unstable nucleus that decay into stable states by emitting radiation in alpha, beta or gamma
define isotone
difference nuclides with same value of neutrons
define metastable
radionuclides being able to exist for a significant period of time with their nucleus in an excited/higher energy state before falling to ground state
define isomer
long-lived excited state of a nuclide
define activity in radioactivity
rate at which nuclei decay/ average number of disintegrations per second
define half-life
average time a radioactive substance takes to decay to half its initial activity
What causes alpha, beta+ (positron emission), beta- decay, electron capture?
alpha decay= too many protons and neutrons
beta- decay= too many neutrons
electron capture/beta+ = too few neutrons
Between particle, gamma ray, electron and x-ray emission, which are considered atomic or nuclear?
particle and gamma ray = nuclear
x-ray and electron = atomic
describe the formation of alpha decay
heavy radionuclide with too many nucleons decay releasing 2 protons and neutrons.
parent atomic mass reduces by 4
parent proton number reduces by 2
forms daughter element and alpha particle
describe the features of alpha particle
+ve charge, relatively heavy, short range and highly ionising
describe formation of beta minus decay
radionuclide with too many neutron decays, converting a neutron into a proton and electron
parent atomic mass stays same
parent proton number increases by 1
forms daughter element and beta - particle (electron)
describe formation of beta plus decay
radionuclide with too few neutrons decay converting a proton into a neutron and positron
parent atomic mass stays same
parents proton number decreases by one
forms daughter element and positron (anti electron)/ beta+ particle
describe electron capture
radionuclide with too few neutrons decay.
K-shell electron is captured by the nucleus
causing proton to be converted into neutron and the emission of an electron neutrino
parent atomic mass stays same
parent proton number stays same
parent element adds electron
forms daughter element with same atomic number but decrease 1 in proton number
How is a gamma ray formed during isomeric transition?
radionuclide in metastable state decays to ground state and during the isomeric decay, the energy difference between excited and ground nuclear states is emitted as gamma ray
what is an alpha, beta + beta- particles?
alpha = helium ion
beta+ = positron
beta- = electron
