1. Section 3: Radioactive Decay and Half-Life

2.  The spontaneous emission of rays or particles from certain nuclei as they “decay,” such as Uranium.  These rays or particles are called nuclear radiation.  They come in three types: Alpha Radiation: Helium nucleus; 2 + Charge; Low power (0.05 mm body tissue) Beta Radiation: electron; 1 - Charge; Moderate power (4 mm body tissue) Gamma Radiation: electromagnetic wave; neutral charge; High Power (penetrates entire body easily)

4.  While the process is spontaneous, it is not instantaneous… it takes time!  The time required for HALF of the atoms of a radioactive substance to decay is called a half-life.

7.  Fluorine 18 ( F) has a half-life of 110 seconds. This material is used extensively in medicine. The hospital laboratory begins the day with 10 grams of F… 18 9 18 9

8. 1 half-life = 110 seconds 660 seconds 110 seconds = 6 half-lives

9.  6 half-lives = 10 divided in half, 6 times 1) 10/2 = 5 grams 2) 5/2 = 2.5 grams 3) 2.5/2 = 1.25 grams 4) 1.25/2 = 0.625 grams 5) 0.625/2 = 0.3125 grams 6) 0.3125/2 = 0.15625 grams After 11 minutes, only 0.16 g of the 10 g sample remain!!!!!!