1. Nuclear Energy Radioactivity and Half-Life FissionFusion

2. Radioactivity The process in which an unstable atomic nucleus emits charged particles and energy. The process in which an unstable atomic nucleus emits charged particles and energy.

3.  Protons and neutrons determine nuclear reactions  One must understand atomic structure to understand radiation NUCLEAR REACTIONS PRODUCE RADIATION 6

4. Radioactive decay refers to the spontaneous emission of radiation from the nucleus of an unstable atomic nucleus Radioactive decay refers to the spontaneous emission of radiation from the nucleus of an unstable atomic nucleus The ratio of neutrons to protons is largely determinant of the stability of the nucleus and the tendency for radioactive decay to occur The ratio of neutrons to protons is largely determinant of the stability of the nucleus and the tendency for radioactive decay to occur RADIOACTIVE DECAY 8

5. Types of Nuclear Radiation Alpha decay Alpha decay Beta decay Beta decay Gamma decay Gamma decay

6. Alpha decay Emits alpha particles which are positively charged particle Emits alpha particles which are positively charged particle Are the least penetrating type of nuclear radiation Are the least penetrating type of nuclear radiation Can be stopped by a sheet of paper Can be stopped by a sheet of paper

7. Beta decay Release of negatively charged particle Release of negatively charged particle Are more penetrating than alpha particles. Are more penetrating than alpha particles. Can be stopped by a thin piece of metal Can be stopped by a thin piece of metal

8. Gamma decay Nuclear radiation consisting of a stream of particles with no charge and very little mass Nuclear radiation consisting of a stream of particles with no charge and very little mass A form of high energy electromagnetic radiation (high frequency & low wavelength) A form of high energy electromagnetic radiation (high frequency & low wavelength) Most penetration power Most penetration power

9. Half-life Is the time required for half of the radioactive substance to decay (as either alpha, beta, and gamma radiation) Is the time required for half of the radioactive substance to decay (as either alpha, beta, and gamma radiation) Nuclear decay rates are constant for specific elements Nuclear decay rates are constant for specific elements Practical uses: Radioactive dating Practical uses: Radioactive dating Examples: Examples: The half-life of isotope X is 2.0 years. How many years would it take for a 4.0 mg sample of X to decay and have only 0.50 mg of it remain? The half-life of isotope X is 2.0 years. How many years would it take for a 4.0 mg sample of X to decay and have only 0.50 mg of it remain?

10. Nuclear Fission Practical Applications

11. Fission Is the splitting of an atomic nucleus into 2 smaller parts Is the splitting of an atomic nucleus into 2 smaller parts Tremendous amounts of energy in the form of gamma rays can be produced from very small amounts of mass Tremendous amounts of energy in the form of gamma rays can be produced from very small amounts of mass Chain reaction-neutrons released during the splitting of an initial nucleus triggers a series of nuclear fissions. Chain reaction-neutrons released during the splitting of an initial nucleus triggers a series of nuclear fissions.

12. Examples Power Plants run off of the fission of Uranium-235 Power Plants run off of the fission of Uranium-235 Nuclear weapons are an example of an uncontrolled chain reaction Nuclear weapons are an example of an uncontrolled chain reaction

13. Fission of Uranium Barium and Krypton represent just one of many potential outcomes

14. Nuclear Disaster- Chernobyl

15. Fusion Is a process in which the nuclei of two atoms combine to form a larger nucleus Is a process in which the nuclei of two atoms combine to form a larger nucleus Can release huge amounts of energy in the form of high energy gamma rays Can release huge amounts of energy in the form of high energy gamma rays

16. Fusion cont. Temperatures are so high that matter exists as plasma. The sun is 10,000,000 degrees Celsius Temperatures are so high that matter exists as plasma. The sun is 10,000,000 degrees Celsius Plasma-a state of matter where atoms have been striped of their electrons. Plasma-a state of matter where atoms have been striped of their electrons. 2 problems are creating high temperatures and containing the plasma 2 problems are creating high temperatures and containing the plasma

17. Stars…