1. Radioactivity

2. Radioactivity
When an atom of an element has an unstable nucleus, the nucleus can disintegrate, forming subatomic particles and releasing large amounts of energy.
This release is called radioactivity
Alpha and beta particles may be released

3. Alpha Particles An alpha particle is a helium nucleus 2 protons
2 neutrons
Symbol is α
Mass is 4 amu
Charge is +2

4. Beta Particles A beta particle is an electron Symbol is β
Mass is insignificant amu
Charge is -1

5. Nuclear Reactions
During nuclear reactions, an unstable element will transform or decay into another element with a lower mass
In this reaction, an alpha particle has been released
This is called an alpha decay reaction

6. Nuclear Reactions
In the second step of this reaction, an electron is released
This is a beta decay nuclear reaction
It takes 12 more decay reactions to reach a stable nuclear structure

7. Gamma Rays
Gamma rays are powerful electromagnetic waves that are emitted when a nucleus disintegrates
They do not transform an unstable element into another element or alter its mass

8. Types of Nuclear Reactions
Nuclear fission
The splitting of a nucleus into two smaller nuclei with a tremendous release of energy
The energy comes from the mass lost when the nucleus is split
Often, neutrons are ejected when the nucleus is split

9. Types of Nuclear Reactions
Nuclear fission

10. Types of Nuclear Reactions
Nuclear fusion
The combining of two smaller nuclei to form a larger single nucleus with a tremendous release of energy – this energy also comes from lost mass
Fusion requires a huge amount of energy and pressure
Occurs naturally in stars like the sun

11. Types of Nuclear Reactions
Nuclear fusion

12. Pros of Nuclear Technology
Used in medicine, weapons and electricity production
Medicine – cancer treatments and diagnostic tests
Electricity – nuclear power plants
Produce large amounts of energy
Little air pollutio

13. Cons of Nuclear Technology
Cooling of electrical plants can result in thermal pollution
Radioactive leaks possible
Fukushima, Japan
Three Mile Island
Dangerous waste must be stored for long periods of time

14. Half-life Radioactive materials decay in a predictable way
The rate of decay is called the half-life of a substance
The half-life is the amount of time it takes half of the substance to decay
Different substances have different half-lives

15. Half-life For carbon-14 (C-14), the half life is 5370 years
If you start with 1000g of C-14, in 5370 years, you will have only 500g left (half has decayed)
After another 5370 years, you will have 250g (half of the 500g)

16. Half-life Activity
We are going to use Skittles to simulate what happens with atoms of radioactive elements