1. Nuclear Decay You will be learning: 1.What is alpha, beta, and gamma radiation. 2.Know the half-life of a radioactive material. 3.How to describe the process of radioactive dating.

2. Nuclear Radiation Three (3) types of radiation –Alpha radiation – particles –Beta radiation – particles –Gamma radiation – electromagnetic wave

3. Alpha Particles Alpha particle - two protons and two neutrons –Massive –Loses energy quickly when it interacts with matter –As it passed through matter, they exert an electrical force on the electrons. Electrons are pulled away from the atom leaving positively charged ions –Least penetrating form of nuclear radiation and may be stopped by a sheet of paper. –Alpha Particle = 4 He 2

4. Alpha particles can easily damage the human body. May lead to illness or disease Smoke detectors give off alpha particles. This creates an electrical current around the detector. Smoke breaks the electrical circuit. Transmutations occurs with the release of an alpha particle. A new element is formed with 2 less protons and 2 less neutrons.

5. Beta Particles Beta decay is when a neutron decays into a proton and emits an electron. A beta particle is the electron that is emitted. This is caused by the weak force. There is now a different element since there is one more proton. Even though you have a different atomic number, the mass number stays the same.

6. Beta particles are faster and more penetrating than alpha particles. Stopped by a sheet of aluminum foil. Both alpha and beta particles can damage living cells.

7. Gamma Rays Gamma rays are electromagnetic waves with the highest frequencies and shortest wave lengths. Have no mass, no charge, and travel at the speed of light. Thick blocks of dense materials, such as lead and concrete are required to stop gamma rays. Cause less damage to living cells. Gamma rays produces fewer ions because there is no electrical charge

8. Radioacative Half-Life Some radioisotopes decay from stable atoms in less than a second. Some radioisotopes take millions of years to decay. The measure of the time required for an isotope to decay is called half-life.

9. Radioactive Dating Radioactive dating is measured by determining the amount of radioactive isotopes and it half- lives. Carbon dating is by comparing the ratio of carbon-14 to carbon-12. The ratio decreases over time. All living matter has carbon-14. Half- life of carbon-14 is 5,730 years. Uranium dating is used in some rocks that contain uranium. Uranium has two isotopes that have long half-lives. The ratio of these two isotopes of uranium calculate the age of the rocks.

11. Which particle can be stopped by aluminum foil? beta

12. ____ is the process of changing one element to another through nuclear decay. transmutation

13. Which particle is formed of 2 protons and 2 neutrons? alpha

14. When a neutron decays into a proton and an electron it is called a _____ particle. beta