Radioactivity Flashcards
what is the mass number
atomic mass number is the total number of nucleons. (n + p)
what is the atomic number
no. of protons
formula for neutrons
atomic mass - atomic number
what are isotopes
atomic of the same element that have the same number of protns but the number of neutrons can be differnet.
Same no of p and diff no of n are called istopes
what forces are present within a nuclues
electrostatic and strong nucleur
what happens with electrostatic forces within nuclues
there is a repulsive force
force can act over large distance
repulsion betwween p+ can tear nuclues apart
what happens with strong nucluer force within nuclues
it is a force of attraction that holds nuclues together
strong nuclues force exists between every nucleon
is stronger than electrostatic force and it acts over very short distances
what is spontaneous transmutation
an unstable nuclues may become stable by changing into a differnet element, releasing a particle as it does so. This process is called spontaneous transmutation. and they emit particles and or radiation that are said to be radioactive
what is alpha decay
when a heavy unstable nucleus undergoes radioative decay, it may eject an alpha particle
what is beta minus decay
it happens when an unstable atom has a relatively large number of neutrons (n>p)
the neutrons splits into a proton, an electron (b-) and an antinuetrino
proton stays in nuclues and other two are emitted
what is beta positive decay
it happens when p>n in an atom
proton decays into a neutron, positron and neutrino
neutron stays in nuclues and the other two are emitted
what is a positron
charge of proton
mass of electron
what is gamma decay
photons (packets of electromagnetic energy) of energy short wavelengths
when does gamma decay happen
when an unstable atomic nuclei dissipates energy by spontaneously emitting gamma rays
why can a nucleus be stable
when there is a balance between repulseive electrostatic force and attractive strong nuclear force
