1. Nuclear Changes
Chapter 9

2. What is Radioactivity?
Radioactivity is the process in which an unstable nucleus breaks apart into two or more new nuclei and energy
The four types of radiation are:
Alpha (a) +2
Beta (b) -1
Neutron emission (10n) no charge (0)
Gamma (g) no charge (0) (pure energy)
Bigger to smaller &
More dangerous!

3. Nuclear Decay
Once the number of protons change the element changes to two or more new ones.
Remember:
So:
Practice Sheet

4. Half-Life
The amount of time that it takes for half of a radioactive element to decrease by half of the original amount.
Is used to measure how quickly substances decay. (Chart p.290)
Carbon-14 is used to date materials by using the carbon content from when the material was alive.
Ex: dinosaurs, mummies, clothing, etc

5. Half-Life continued… What is one half-life for carbon-14?
What is emitted from potassium-40?
How long is three half-lives of iodine-131?
If a 100 g sample of radon-222 is left out for days, how much of the sample would be left?

6. Fission vs. Fusion
Fission is the large release of energy by the splitting of atoms
much more dangerous because of high temperatures involved
Fusion is the small release of energy by combining atoms together
much saver but we do not have the technology to harness this energy and the amounts are smaller

7. Uses for Radiation Smoke detectors
Radioactive tracers to detect disease p.301
Treat cancer
Radioactive tracers to track water to crops

8. Risks of Radiation Overexposure Table 4 p. 300 Location Table 3 p.300
A safe limit for radiation is 5000 rems a year!!!