1. Nuclear Radiation Natural Radioactivity Nuclear Equations
Producing Radioactive Isotopes
Half-Life
Nuclear Fission and Fusion

2. Subatomic Particles Protons- plus charge In the nucleus
Neutrons- neutral
Electrons - negative charge
Outside the nucleus

3. Radioactivity
Spontaneous emission of rays or particles from certain elements, such as U

4. Nuclear Radiation Unstable nucleus emits a particle or energy  alpha
 beta
 gamma

5. In both chemical reactions and nuclear reactions, the atom becomes MORE STABLE.
Not likely to change

6. Radioisotopes Nuclear reactions start with unstable isotopes.
Are not affected by changes in T, P or the presence of a catalyst!

7. Same as a helium nucleus
Alpha Particle
Same as a helium nucleus
(He) 4
2 He or 
Two protons
Two neutrons

8. Alpha decay

9. Beta Particle  e or  1 An electron emitted from the nucleus
e or  1
A neutron in the nucleus breaks down
n H + e

10. Beta decay
234Th ® 234Pa e 1
beta particle

11. Gamma  Radiation Pure radiation High energy, no mass or charge
Like an X-ray but comes from the nucleus

12. No change in atomic or mass number
Gamma radiation
No change in atomic or mass number
11B 11B 
boron atom in a
high-energy state

13. Radiation Protection Shielding alpha – paper, clothing
beta – lab coat, gloves
gamma- lead, thick concrete
Limit time exposed
Keep distance from source

14. Radiation Protection

15. Balancing Nuclear Equations
In the reactants and products
Atomic numbers must balance
and
Mass numbers must balance

16. Example
Write the nuclear equation for the beta emitter Co-60.

17. Solution 60Co 60Ni + 0 e 27 28 -1 Write the nuclear equation for the
Beta emitter Co-60.
60Co Ni e

18. EXIT QUIZ

19. 1. If I have 72 liters of gas held at a pressure of 3
1. If I have 72 liters of gas held at a pressure of 3.4 atm and a temperature of 225 K, how many moles of gas do I have?

20. 2. The final elements produced by radioactive decay differ from the original radioactive elements because the nuclei of the final elements are always?
A. More stable
B. Increased in mass
C. Half as radioactive
D. Positively charged

21. Producing Radioactive Isotopes
Bombardment of atoms produces radioisotopes
= = 60
59Co n Mn H e
= = 27
cobalt neutron manganese alpha
atom radioisotope particle

22. Learning Check NR2
What radioactive isotope is produced in the following bombardment of boron?
10B He ? n

23. Solution NR2
What radioactive isotope is produced in the following bombardment of boron?
10B He N n
nitrogen
radioisotope

24. Half-Life of a Radioisotope
The time for the radiation level to fall (decay) to one-half its initial value
decay curve
8 mg 4 mg 2 mg mg
initial 1
half-life 2 3

25. Examples of Half-Life Isotope Half life C-15 2.4 sec Ra-224 3.6 days
I days
C years
U years

26. Learning Check NR3
The half life of I-123 is 13 hr. How much of a 64 mg sample of I-123 is left after 26 hours?

27. Solution NR3 t1/2 = 13 hrs 26 hours = 2 x t1/2 Amount initial = 64mg
Amount remaining = 64 mg x ½ x ½
= 16 mg

28. Nuclear Fission Fission large nuclei break up
235U n Ba Kr + 3 1n +
Energy

29. Fission

30. Nuclear Fusion Fusion small nuclei combine 2H + 3H 4He + 1n + 1 1 2 0
Occurs in the sun and other stars
Energy

31. Learning Check NR4 Indicate if each of the following are
Fission (2) fusion
Nucleus splits
Large amounts of energy released
Small nuclei form larger nuclei
Hydrogen nuclei react
Energy

32. Solution NR4 Indicate if each of the following are Fission (2) fusion
Nucleus splits
Large amounts of energy released
Small nuclei form larger nuclei
Hydrogen nuclei react