 Inside


the nucleus there are:
Protons
Neutrons
 The
nucleus is held together by the strong
nucleus force.
The nucleus is not always
stable!
 The number of protons and
neutrons can influence the
stability of the nucleus.




Usually a 1:1 ratio is stable.
More than this is unstable
Certain isotopes of elements are
said to be unstable, and as a
result they break down 
radioactive.

All elements with an atomic number
above 82 have at least one
radioactive isotope.
 There
are three major types
of radioactivity:


Composed of 2 protons and 2
neutrons
A helium nucleus
Made of a single negative charge
 Basically an electron

High energy photon
 No mass

 Alpha
particles lost:
A nucleus loses 2 protons and 2 electrons
 This produces a loose alpha particle and an atom that is
“lighter” with an atomic number lower by two and an
atomic mass lower by 4 amus.

 Beta



particles lost:
A neutron is made up smaller particles
In radioactive isotopes sometimes a neutron will
spontaneously break apart, releasing a beta
particle (electron).
What remains is a proton
The neutron breaks apart into
a proton and an electron.
The electron is released from
the nucleus and the proton
stays.
 Gamma
Rays:
The most penetrating and high energy type of radioactivity.
 Large amounts of photon energy is released
 The nucleus is unchanged in numbers of protons and
neutrons, but becomes more stable.

 Alpha
particles are the most heavy but least
penetrating.
 Gamma rays are pure energy, have no mass, but
are the most penetrating.
 1.
Fission: This occurs when a radioactive
nucleus splits to form two smaller, more
stable nuclei
 This
can lead to dangerous chain reactions!
A
common source of
Uranium-235 is used as a
fuel in nuclear reactions.
 It
undergoes a number of
reactions to release a great
deal of energy, which in a
reactor is harvested and
used for power.
 Another
common source of
fuel is Uranium-238
 The
end result of all of the
reactions is a stable isotope
of lead!

2. Fusion: This type of reaction involves
two small nuclei coming together to form a
larger nuclei.

This is how the sun works
 Nuclear
fusion produces an
enormous amount of energy,
more than fission.
 However
the reaction is very
unstable and dangerous.
 Can
only be contained in stars
like the sun.