Question #577df

1 Answer
Feb 5, 2017

Radioactivity is the process by which the (unstable) nucleus of an atom disintegrates (i.e. breaks down to form different particles/ releases energy).


In short, if a nucleus of an atom decays spontaneously, it is deemed radioactive. For instance, unstable thorium or carbon-14 nuclei often decay and are, therefore, radioactive. There are three common forms of such radioactive decay:

  • Alpha decay: an alpha particle is released
  • Beta decay: an electron or positron (positive electron)
  • Gamma decay: a photon/high energy particle is released

For example (alpha-decay):

In all cases, radioactivity is present as:

  • An unstable nucleus has decayed (in the example above, the uranium nucleus decays into thorium)
  • A particle (in the example above, a helium nucleus/alpha particle) or energy (gamma) has been released