Download Nuclear Chemistry – Chapter 25, chapter 4, section 4

Nuclear Chemistry
Nuclear chemistry is the study of the changes of the __________________ of atoms.

Nuclear Reactions involve changes within the nucleus where as chemical reactions involve the
loss, gain or sharing of electrons.
The Nucleus
 Contains ________________ and neutrons. They are collectively called
_____________________.
Radioactivity
 A _____________________ nucleus holds together well. An unstable nucleus will decay or
break down, releasing particles and/or energy in order to become stable.
 An atom with an unstable nuclei is considered “_____________________”.
There are several ways radioactive atoms can decay into different atoms!
Transmutation
 Type of nuclear reaction that will change the number of ___________________ and thus will
create a different ________________________.
BasicTypes of Radioactive Decay
Particle Type
Symbol
What Happens?
Atomic
Alpha
number
decreases
by ____
and mass
or
number
decreases
by ____
Atomic
***Beta
number
increases
by _____
but the
mass
or
number
stays the
same
Example
Penetrating Power
(1) LOW: Can be
blocked by
paper/clothing
(100) MEDIUM: can
penetrate the skin;
need to be protected
by clothing/thin
metals like aluminum
Gamma
No change
in atomic
nor mass
number;
occurs with
other types
of decay
(100000) HIGH:
need to be protected
by thick concrete or
metal like lead
*** A neutron becomes a ________________ and a high speed electron that is discharged from the
nucleus.
Writing Balanced Nuclear Equations
The ______________________ and mass number must be _____________________ on both sides of
the equation.
Alpha Decay of thorium-230
Beta Decay of cesium -137
You Try!
1. Beta decay of zircomium-97
2. Alpha decay of americium-241
3. Alpha decay of uranium-238
4. Complete this: 239
239
Np 
93
Pu
+ ___________
94
Bombarding the Nucleus

All the transuranium elements (elements with atomic numbers higher than Uranium) have been
made by bombarding the nucleus with neutrons and other atoms in accelerators
Example:
Half Life
 Radioactive isotopes decay at a characteristic rate measured in ____________________.
 A half life is the time required for _____________ of the amount of radioactive atoms to decay.
The time ranges from __________________ to millions of _____________________.
T= elapsed time
T1/2 = half life
HOW TO’s
1. To calculate the number of half lives, divide the half life (T1/2) into the total time (T).
T/T1/2 = # of half lives
2. Equation to calculate remaining amount left over after a certain number of half lives have passed.
Amt remaining = (initial amt) (.5)n (# of half lives)
__________________________________________________________________________
Examples:
1. Suppose you have 20 grams of sodium-24. Its half-life is 15 hours. How much is left over after 60
hours.
2. Uranium-238 has a half life of 4.46 x 109 years. How long will it take for 7/8th of the sample to
decay?
You Try!
The half life of radium-222 is 38 s. How many grams of a 12.0 g sample are left after 114 s?
Nuclear Fusion
 Smaller atoms are _______________________ to form a
large atom.
 Occurs in the _____________and _____________
 Generates huge amounts of ____________________
Nuclear Fission
 Large atoms _______________ into smaller atoms
 Generates huge amounts of ___________________.
 Carried out in ___________________
Could result in a chain reaction of fission
like the _____________________
Tutorials:
NuclearReactions:http://ithacasciencezone.com/chemzone/lessons/11nuclear/dcayquiz.htm
Half Life & Nuclear Reactions: http://www.glencoe.com/qe/science.php?qi=2696\