1. Nuclear Reactions

2. Natural Transmutation
1 term on reactant side
Original isotope
2 terms on product side
Emitted Particle
New Isotope
Happens all by itself (spontaneous)
Not affected by anything in environment

3. Natural Transmutation
16N  0e O 7 -1 8
2 terms on product side
1 term on reactant side

4. Artificial Transmutation
Cause it to happen by smashing particles into one another
2 terms on reactant side
Original Isotope
Particle that hits it
neutron, proton, or -particle
Product side: usually 2 terms

5. Artificial Transmutation
27Al He  30P + 1n 15 13 2
Original isotope or target nucleus
“Bullet”
-what hits isotope

6. Artificial Transmutation
27Al + 4He  30P + 1n
All of these equations have
2 reactants! 13 2 15
14N + 4He  17O + 1H 1 2 8 7
75As + 4He  78Br + 1n 2 35 33
37Cl + 1n  38Cl 17 17

7. Bombarding with Protons or 
Protons and -particles have positive charge and mass
do some damage when hit target nucleus
must be accelerated to high speeds to overcome repulsive forces between nucleus & particle (both are +)

8. What is an accelerator? vacuum chamber (usually a long pipe)
surrounded by vacuum pumps, magnets, radio- frequency cavities, high voltage instruments and electronic circuits
inside the pipe particles are accelerated to very high speeds then smashed into each other

9. Splitting heavy nucleus into 2 lighter nuclei
Fission Reaction
Splitting heavy nucleus into 2 lighter nuclei
Requires a critical mass of fissionable isotope
Controlled – nuclear reactor
Uncontrolled – bomb

10. Fission Reactant side: 2 terms Product side: at least 2 terms
1 heavy isotope (examples: U-235 or Pu-239)
Bombarding particle – usually a neutron
Product side: at least 2 terms
2 medium-weight isotopes
1 or more neutrons
Huge amount of energy is released
Fission = Division

11. Fission 235U + 1n  91Kr + 142Ba + 31n + energy 56 92 3692 36
235U + 1n  72Zn + 160Sm + 41n + energy 62 92 30
More than 200 different product isotopes identified from fission of U-235
A small amount of mass is converted to energy according to E = mc2

12. Fission Chain Reaction

13. Fusion Reactant side has 2 small nuclei: Product side:
H + H; H + He; He + He
Product side:
1 nucleus (still small) and maybe a particle
Source of sun’s energy
2 nuclei unite
2H + 3H  4He + 1n + energy 2 1 1

14. CERN 27 kilometer ring Particles travel just below speed of light
In 10 hrs: particles make 400 million revolutions of the ring

15. FermiLab
4 miles in circumference!

17. Balancing Nuclear Equations

18. Nuclear Equations - tasks
Identify type (4 types)
Balance to find 1 unknown term

19. Natural Transmutation – ID
1 term on reactant side
starting isotope
2 terms on product side
ending isotope and emitted particle
Type of particle emitted characteristic
of isotope – Table N

20. Nuclear Equations
To balance: use conservation of both atomic number & mass number
Mass number = left superscript
Atomic Number = left subscript

21. Balancing Nuclear Equations
16N  0e O -1 7 8
Conservation of mass number: 16 =
Conservation of atomic number: 7 =

22. Writing Equations Write the equation for the decay of Thorium-232
Use Table N to find the decay mode: α
Write the initial equation:
232Th  4He + X 90 2
figure out what element it turned into

23. What’s under the hat?
Little cats X, Y, & Z!

24. Write an equation for the α decay of Am-241
241 Am  4He + YX
What’s X? 95 2 Z

25. so Y = 228 232 = 4 + Y Conservation of Mass Number:
232Th  4He X Y Z 90 2
Conservation of Mass Number:
sum of mass numbers on left side must = sum of mass numbers on right side

26. so Z = 88 90 = 2 + Z Conservation of Atomic Number:
232Th  4He + 228X 90 Z 2
90 = Z
so Z = 88
Conservation of Atomic Number:
sum of atomic numbers on left side must = sum of atomic numbers on right side

27. 232Th  4He + 228X 90 2 88
Use the PT to find X:
X = Ra
232Th  4He + 228Ra 90 2 88

28. Alpha (α) decay: 233U  229Th + 4He 232Th  228Ra + 4He
232Th  228Ra + 4He
175Pt  171Os + 4He

29. How does the mass number or atomic number change in α,β or γ decay?
go to Table N:
find isotope that decays by alpha or β decay
write the equation
see how the mass number (or atomic number) changes
22688Ra  42 + X so X has to be 22286X
X is Rn-222
mass number decreases by 4; atomic number decreases by 2

30. Write an equation for the  decay of Am-241
so Y = 237
241 Am  4He + YX 95 2 Z
so Z = 93
95 = Z
What’s X?
X = Np

31. Radioactive Decay Series
Sometimes 1 transmutation isn’t enough to achieve stability
Some radioisotopes go through several changes before they achieve stability (and are no longer radioactive)

33. β C  14N + 0e 6 7 -1
β F  18O + 0e 9 8 +1

34. How does the mass number or atomic number change in  or  decay?
Go to Table N; find an isotope that decays by α,  or , write the equation; see how the mass number (or atomic number) changes
226Ra  4 + X so X has to be 222X
X is Ra-222
mass number decreases by 4
atomic number decreases by 2 88 86 2