Download Nuclear Radiation

Nuclear Radiation
Half-Life
What is Radiation?
• Penetrating rays
and particles
emitted by a
radioactive source
• Result of a nuclear
reaction!
– Involves the
changing of the
atoms nuclei
Radioisotopes
• Isotopes
– Elements with the
same # of protons
& electrons, but a
different # of
neutrons!
• Radioisotopes
– Unstable isotopes
– In nuclear rxns their
nuclei undergo
changes to become
stable
Chemical vs. Nuclear rxns
Chemical Rxns
Nuclear Rxns
• Involve the transfer
or sharing of e-
• Nuclei are changed
to become stable
• Nuclei are
unchanged
• Involve large
amounts of energy
being emitted
• Affected by ∆ in
temp, pressure &
catalyst
• Not affected by
anything & cannot
be stopped
Nuclear Stability
• Depends on the ratio of neutrons to protons
in the nucleus & the overall size of the
nucleus
• Too many or too few neutrons makes the
nucleus unstable
• Unstable nucleus releases energy by
emitting radiation during radioactive decay!
Types of Radiation
• 3 main types:
• Alpha Radiation
• Beta Radiation
• Gamma Radiation
Alpha Radiation
• Occurs when a
helium nuclei is
emitted
– Called “alpha”
particals
• Product atoms
atomic # is lower
by 2 & its mass # is
lower by 4
• Are stopped by
paper!
Beta Radiation
• e- released when a
nucleus breaks apart
• Product atom has the
same atomic mass,
but the atomic #
increases by 1
• Less mass than an
alpha particle & can
penetrate paper, but
are stopped by wood
or aluminum foil
Gamma Radiation
• High energy
photons
– Electromagnetic
radiation
• Have no mass or
charge, so atomic
# is unchanged
• VERY
DANGEROUS!
– Can penetrate even
wood!
Nuclear Decay
• Nuclear force
Attractive force
between protons &
neutrons that are
really close together
in the nucleus
• Stronger than the
electromagnetic
repulsions
• Keeps nucleus
together!
Half-Life
• Time it takes for
half of the nuclei to
decay into its
stable daughter