Nuclear Chemistry
Bravo – 15,000 kilotons
CA Standards
Students know the three most common forms
of radioactive decay (alpha, beta, and gamma)
and know how the nucleus changes in each type
of decay.
Students know alpha, beta, and gamma
radiation produce different amounts and kinds
of damage in matter and have different
penetrations.
Students know some naturally occurring
isotopes of elements are radioactive, as are
isotopes formed in nuclear reactions.
Nuclear Symbols
Element
symbol
Mass number
(p+ + no)
235
92
U
Atomic number
(number of p+)
Types of Radioactive Decay
alpha production (a, He): helium nucleus
U  He 
238
92
4
2
234
90
Th
beta production (b, e):
Th 
234
90
234
91
Pa  e
0
1
 gamma ray production (g):
U  He 
238
92
4
2
Th  2 g
234
90
0
0
Nuclear
Stability
Decay will occur in
such a way as to
return a nucleus to
the band (line) of
stability.
Alpha
Radiation
Alpha decay is
limited to VERY
large, nuclei
such as those in
heavy metals.
Beta
Radiation
Beta decay
converts a
neutron into a
proton.
Alpha Particle
Emission
Symbol
4
2
Mass
He
2
a
4
or 2
2
Heavy
How it changes 
the nucleus

Decreases the 
mass number
by 4
Decreases the 
atomic number
by 2
Beta Particle
Emission
0
0
1
or 1
Gamma Ray
Emission
Light
No Mass
b
e
Converts a
neutron into a
proton
Increases
atomic number
by 1
0
0
g
No change to the
nucleus
Penetration
Low
Medium
High
Protection
provided by…
Skin
Paper, clothing
Lead
Danger
Low
Medium
High
CA Standards
Students know protons and neutrons in the
nucleus are held together by nuclear forces
that overcome the electromagnetic repulsion
between the protons.
Students know the energy release per gram of
material is much larger in nuclear fusion or
fission reactions than in chemical reactions.
The change in mass (calculated by E = mc2) is
small but significant in nuclear reactions.
Fission
Fission - Splitting a
heavy nucleus into two
nuclei with smaller mass
numbers.
Deuterium – Tritium Fusion Reaction
Fusion - Combining two light nuclei to
form a heavier, more stable nucleus.
Energy and Mass
Nuclear changes occur with small but measurable
losses of mass. The lost mass is called the mass
defect, and is converted to energy according to
Einstein’s equation:
DE = Dmc2
Dm = mass defect
DE = change in energy
c = speed of light
Because c2 is so large, even small amounts of
mass are converted to enormous amount of
energy.
A Fission Reactor