Content Objectives
  Chemistry students wbat compare an element
to its isotope.
  Chemistry students wbat identify the types of
nuclear radiation.
  Chemistry students wbat describe the types of
decay reaction by doing Nuclear Chemistry in
pairs.
  Chemistry students wbat distinguish between
nuclear fission and fusion.
Language Objectives
  You will calculate the number of protons,
neutrons, or atomic mass in an isotope.
  You will determine the half life of radioactive
isotopes.
  You will manipulate terms and definitions as
they relate to nuclear chemistry.
  You will relate the type of nuclear particle to
the decay reaction in pairs.
What the heck is it?
 The study of
changes in the
nucleus of an
atom and the
energy
transformations
that result from
these changes.
Decay Series
Decay series is a series of radioactive
nuclides produced by successive
radioactive decay until a stable nuclide is
reached.
Nuclides
•  Parent Nuclide
The heaviest nuclide of
each decay series.
•  Daughter Nuclides
The nuclides produced by
the decay of the parent
nuclides.
 A change in the identity of the
nucleus as a result of a change
in the number of protons.
Parts of an Atom and what they
tell us
Parts
Atomic number = # of protons
  Nucleus
  Proton (+) = 1 amu
  Neutron (0) = 1 amu
  Cloud (Orbitals)
  Electron (-) = 0 amu
Atomic Mass (mass number)
=
# protons + # neutrons
Quick Review on Isotopes
Generic Isotope
X
A
Z
  X=Element
  A=mass number=#protons +
#neutrons
  Z=atomic number=# protons
Example:
14
6
C
Number of protons =6
Number of neutrons = 8
  Or it can be written:
Element-mass number
Example:
Iodine-131
# of protons = 53
# of neutrons = 78
Mass number
(p+ + no)
Atomic number
(number of p+)
Element
symbol
Heavy
Light
No Mass
•  Decreases the
mass number
by 4
•  Decreases the
atomic number
by 2
•  Converts a
neutron into a
proton
•  Increases
atomic number
by 1
No change to the
nucleus
Low
Medium
High
Skin
Paper, clothing
Lead
Low
Medium
High
Alpha decay is
limited to VERY
large, nuclei such
as those in heavy
metals.
 Positively charged. 2+
 High energy, relatively low velocity.
 Range about 5cm in air
 Stopped by paper, skin.
An alpha particle is 2 protons and 2 neutrons bound together and
is emitted from the nucleus during some kinds of radioactive decay.
4
2
210
84
Po
206
82
He
Pb +
4
2
He
The particle that decays gives off one 4 He
2
So the equation looks like this:
1. 
2. 
210
84
Po
4
2
He +
4
2
He
4
2
He +
4
2
He +
A
ZX
206
+Z X
206
X
82
206
82
Pb
(check the atomic # on periodic table)
So the new nuclide has 2 less neutrons and protons
Beta decay
converts a
neutron into a
proton.
  Fast Electron
  Negatively charged 1  Ejected when a neutron decays into a proton
and an electron.
  High velocity, low energy.
  Range: 30-40 feet
  Stopped by 1cm of aluminum or the thickness
of the average book.
1. 
2. 
3. 
14
6
Look at the particle that is decaying.
Keep the mass number the same and add one to the
number of protons.
So the equation looks like:
C
0
-1
e +
0
-1 e
0
-1 e
A
ZX
+ 14
X
Z
14
+ 7 N (check periodic table for identity of element)
So the mass number stays the same and the
atomic number increases by 1
  Electromagnetic radiation identical with
light
  High energy
  No Charge
  Usually emitted with beta particles; after
the beta is emitted.
  Range: no specific
  Stopped by 5 inches of lead.
They are much like
visible light but a
much shorter
wavelength and
much higher
energy.
So Which one is “best”?
In electron capture, an inner orbital
electron is captured by the nucleus of its
own atom.
106
47
Ag +
0
-1
e
106
46
Pd
Nuclear fission is when a very heavy
nucleus splits into more-stable
nuclei of intermediate mass.
Nuclear fusion is when a light-mass
nuclei combine to form a heavier,
more stable nucleus.
Deuterium – Tritium Fusion Reaction
Natural Decay
  Atomic number may increase or
decrease depending on the type of
decay.
  If the atomic number increases=beta
decay
  If the atomic number decrease=alpha
decay
Half life is the time required for half the atoms of a
radioactive nuclide to decay.
You can find the half life with this equation:
Amount
left at
time T
Original
amount
Time/half life
Half life
  The length of time it takes for half of the given
sample to decay.
  So…….
iodine-181 half life 8 days
Day 0
50 g
Day 8
25 g
Day 16 12.5g
Day 24
6.25g
Day 32
3.125g
Day 40
1.5625g
Etcetera
Exit Ticket
  Which type of radiation can be blocked
by a sheet of paper?
  Does nuclear fusion or nuclear fission
combine the nuclei?
Sources of info and images
  Science geek
  http://faculty.weber.edu/bdattilo/shknbk/notes/
time.htm
  http://www.deq.idaho.gov/inl_oversight/radiation/
penetration.cfm
  http://www.odec.ca/projects/2007/pete7o2/
Background.html
  http://www.euronuclear.org/info/encyclopedia/d/
daughtersandgrand.htm