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)
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