1. What are Isotopes? How are they used ? Learning Goal: Students will define and describe the characteristics of isotopes. …and a song to cheer you up! http://www.youtube.com/watch?v=GFIvXVMbII0&feature=related http://www.youtube.com/watch?v=GFIvXVMbII0&feature=related

2. Atoms with the same atomic number but with different atomic masses are called isotopes Another way to say it: Atoms of the same element with differing numbers of neutrons

3. Isotope: one of two or more atoms having the same number of protons but different numbers of neutrons or Na-23 or Na-24

4. Isotopes have identical chemical properties, yet have very different nuclear properties. Remember: Protons determine the element Electrons determine the chemical properties Neutrons determine the isotope

5. For example, there are three isotopes of hydrogen. Two of these isotopes are stable, (Hydrogen and Deuterium are not radioactive), but tritium (one proton and two neutrons) is unstable.

6. Many elements have stable isotopes, but some are unstable and radioactive. Radioactive isotopes can also be created for many elements.

7. What are isotopes used for??? Mostly in medicine Archeology to date how old things are Smoke detectors Irradiation in pest control Food irradiation Agriculture application – radioactive tracers http://www.chem.duke.edu/~jds/cruise_chem/nuclear/uses.html

8. What is Alpha radiation? Alpha decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle (two protons and two neutrons bound together into a particle identical to a helium nucleus) and is the most energetic but least penetrating form of radiation. It can be stopped by a sheet of paper and cannot penetrate human skin What is beta radiations? An electron emitted when a neutron becomes a proton, moving at nearly the speed of light. Beta particles can penetrate paper or several millimeters of skin, and like alpha particles, are very dangerous when substances emitting them are ingested or inhaled What is gamma radiation? High energy electromagnetic radiation that is emitted from an atom's nucleus has no mass or electrical charge has high penetrating power, and can pass though the human body What is Positron radiation? A positively charged electron-sized particle is emitted from a proton in the nucleus, changing that proton to a neutron.

9. Review Every Chlorine (Cl) atom has 17 protons, without exception, but not every Chlorine atom has 18 neutrons. –Atoms with the same # of protons but contain different #s of neutrons are called isotopes. Since isotopes of an element have different numbers of neutrons they have different massesSince isotopes of an element have different numbers of neutrons they have different masses

10. Using a Geiger Counter to show gamma, beta, alpha radiation: http://www.youtube.com/watch?v=kaS11fW7nNc http://www.youtube.com/watch?v=kaS11fW7nNc A great song showing more about gamma, beta, and alpha radiation: http://www.youtube.com/watch?v=J8p7OIdyt54 http://www.youtube.com/watch?v=J8p7OIdyt54 More of the Element Song: http://www.youtube.com/watch?v=DYW50F42ss8&feature=related