Atoms & ionising radiation

Atoms & ionising radiation

1. Isotopes are different forms of the same element

   • Isotopes are atoms with same number of protons but different number of neutrons
     • Hence the same atomic number but different mass numbers
       • Atomic number is the atoms number of protons
       • Mass number is the atoms' protons + neutrons
   • Isotope example - carbon 12 & carbon 14:
   • Most elements have different isotopes but usually there's only one or two stable ones
     • The other isotopes tend to be radioactive so decay into other elements and give out radiation
       • Radioactivity is a random process
         • Radioactive substances give out radiation from their atoms nuclei - no matter what's done to them
           • This process is entirely random and means if you have 1000 unstable nuclei you don't know when a single one will decay and neither can you cause a decay
           • Totally unaffected by physical conditions such as temperature or any sort of chemical bonding etc
           • Radioactive substances give out one or more of the three types of radiation(alpha, beta or gamma)

2. Background radiation - Radiation that's always present, all around us comes from:

   • Radioactivity of naturally unstable isotopes - in the air, in food and in rocks under are feet; literally all around us
   • Radiation from space, known as cosmic rays these mostly come from the sun
   • Radiation due to man-made sources E.G fallout from nuclear weapon testing, nuclear accidents(chernobyl) or dumped nuclear waste