1. Chemistry 2 Honors Northwestern High School J. Venables
Nuclear Processes
Chemistry 2 Honors
Northwestern High School
J. Venables

2. Radioactivity Discovered by Marie and Pierre Curie Radioactive Decay
Radiation – the rays and particles given off
Radioisotopes – the unstable nuclei that produce radiation
Radioactive Decay
An unstable nucleus gives off radiation
The nucleus changes into a different, more stable nucleus
Spontaneous process

3. Types of Radiation
Type of Radiation
Symbols
Particle
Alpha
Beta
Gamma

4. Types of Radiation Type of Radiation Symbols Particle Alpha α
Helium nucleus
Beta β
electron
Gamma γ
High energy electromagnetic radiation

5. Relative Penetrating Power of Radiation Types

6. Chemical Reactions vs. Nuclear Reactions
Involve changes in electrons (gain, loss, share).
Can gain or lose energy
Products contain same elements as reactants
Nuclear reactions
Involve changes in the nucleus (protons and neutrons).
LARGE energy changes
Elements change into other elements.

7. Chemical nuclear

8. Balancing Nuclear Equations
The sum of the mass numbers on each side of the equation must be equal.
The sum of the atomic numbers on each side of the equation must be equal.

9. Alpha Decay
Examples – Complete the equations for alpha decay:

10. Beta Decay
Examples – Complete the equations for beta decay:

11. Gamma Decay
Has no effect on atomic number or mass number. Generally accompanies alpha or beta decay.

12. Half-Life
The amount of time it takes for one half of a radioactive nucleus to decay.
Example – If you start with 1000 kg of 235U, the half-life is the amount of time that passes before you have 500 kg left.
222Rn decays by alpha decay with a half-life of 3.8 days.
Write a balanced equation.
If you start with 10.0 g of 222Rn, how much will be left after 15.2 days

13. Radiocarbon dating
14C has a half-life of 5730 years. While living, organisms maintain constant 14C levels. Upon death, 14C levels drop as the isotope decays.
Measure the amount of 14C left, and determine when the object stopped living.

14. Transmutation
A nucleus changes into a different element. Happens in one of two ways:
1. Radioactive decay
2. Bombardment

15. Nuclear Fission
A large nucleus splits into smaller, more stable nuclei.
Started by neutrons striking the unstable nucleus.
Chain reaction – neutrons produced.
Used to create electricity (fission of )
Can be controlled
Used in nuclear weapons (uncontrolled)

16. Nuclear Fusion
Two small nuclei are fused (combined) to form a larger, more stable nucleus
Requires large amounts of energy to start (only occur at very high temperatures)
Produces VERY large amounts of energy.
The process by which the sun produces energy.

17. Examples – complete the following nuclear equations