1. Radioactive Decay

2. Radioactive Decay
Some isotopes (atoms with the same # of _______ but different # of ________) are unstable, meaning their nuclei don’t hold together well
In radioactive decay, radiation is spontaneously released from an atom’s nucleus in the form of different particles

3. Three Types of Radiation
Alpha: ___ charge
Beta: ___ charge
Gamma: ____ charge

4. Alpha Particles Made up of 2 neutrons, 2 protons
When an atom loses an alpha particle, its atomic number drops by 2
Polonium-210 (atm. #84)  Lead-206 (atm. #82)

5. Penetrating Power of Radiation

6. Radioactive Tracers
Because radiation can be observed, a radioactive isotope can be used to follow the steps of a chemical reaction.
Tracers are radioactive isotopes used to trace the steps of a reaction. Doctors use tracers to find medical problems and kill unhealthy cells.
Ex: technetium-99 used to diagnose problems in bones, liver, kidneys

7. Cancer and Gamma Radiation
After cancerous cells are located, doctors can use radioactive gamma rays to kill these harmful cells.
High energy gamma rays, such as cobalt- 60 can be directed at cancerous tumors, causing a powerful change that can kill cancer cells.

8. Radioactive Carbon Dating
Scientists can determine the age of natural materials found on earth by determining the half-life of certain atoms.
The half-life of an isotope is the length of time needed for half of the atoms of a given sample to decay. It is different for different elements.
Radioactive dating is the process of determining the age of an object by using the half-life of its radioactive isotopes. The most common isotope used to determine the age of a fossil is carbon-14.