1. Nuclear Radiation

2. Radiation Radiation comes from the nucleus of an atom.
Unstable nucleus emits a particle or energy  alpha
 beta
 gamma

3. Same as a helium nucleus
Alpha Particle
Same as a helium nucleus 4
2 He or 
Two protons
Two neutrons
Mass number
Atomic number

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

5. Positron Particle The antiparticle counterpart to the electron
Has an electric charge of +1 0e +1 0b or
positron

6. Gamma Radiation  Pure radiation
Like an X-ray but comes from the nucleus

7. Radiation Protection Shielding alpha – paper, clothing
beta – lab coat, gloves
gamma- lead, thick concrete

8. Radiation Protection

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

10. Alpha decay

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

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. Learning Check
Write the nuclear equation for the beta decay of Co-60.

14. Solution
Write the nuclear equation for the Beta decay of Co-60.
60Co Ni e

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

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

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

18. 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

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

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

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

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

23. Fission

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

25. Learning Check 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

26. Solution 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