Key Concepts
occur to the nuclei of atoms,
NOT their electronic structure
 Nuclear reactions produce radiation
and a different element
 Radioactive decay is the spontaneous
decay of an element, forming a new
element
 Changes
Nuclear Transformations III
 transmutation
Key Concepts
The α decay of
Radium-226 to Radon-222
 Example:
 226
88Ra
→
222
86Rn
4
+ 2He
Types of transmutations
 Natural
transmutation
 Occurs
with elements that have an
atomic number 83 or greater
The α decay of
Plutonium-242
 Example:
 24294Pu
Types of transmutations
 Artificial
transmutation
bombardment of an
element with high speed particles
in a particle accelerator
 Artificial
 Example: Aluminum
with a β- particle
 2713Al
bombarded
+ 0-1e → 2712Mg
→ 23892U + 42He
Types of transmutations
 It is easy to tell the difference
between natural and artificial
transmutation
 Natural
 24294Pu
→ 23892U + 42He
 Artificial
 2713Al
+ 0-1e → 2712Mg
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Nuclear Equations
 Nuclear
reactions must obey the laws
of conservation of mass and charge!
 147N + 42He → 178O + 11H
 Massreact
 (14
= Massprod
Problem
 What is represented by X in the
following nuclear reaction?
 2713Al
+ 10n → 2411Na + X
+ 4) = (17 + 1) = 18 amu
 NCreact
= NCprod
 (7 + 2) = (8 + 1) = +9
Problem
 2713Al + 10n → 2411Na + X
of mass and charge
 X must have a mass of 4
 X must have a charge of +2
 X must be an α particle: 42He
Solution
 2713Al
+ 10n → 2411Na + 42He
 Conservation
 2713Al
+ 10n → 2411Na + 42He
Solution
 2713Al
+ 10n → 2411Na + 42He
 Artificial
transmutation
 The Al is being bombarded with
a 10n
 Is
this process an example of
natural transmutation or artificial
transmutation?
 How can you tell?
Problem
 What is represented by X in the
following reaction?
 1910Ne
→ 199F + X
2
Problem
 1910Ne → 199F + X
of mass and charge
 X must have a mass of 0
 X must have a charge of +1
 X must be a positron
 Conservation
 1910Ne
Solution
 1910Ne
→ 199F + 0+1e
 Is this process an example of
natural transmutation or artificial
transmutation?
 How can you tell?
→ 199F + 0+1e
Solution
 1910Ne
→ 199F + 0+1e
 Natural
transmutation
 1910Ne isn’t being bombarded with
anything – occurs naturally
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