1. Half-Life

2. Half-Life
Time required for ½ of any given mass radioactive nuclei to decay
Characteristic for each isotope
Ranges from fractions of second to billions of years
Not affected by chemical or physical environment

3. Half-Life Map 1 1 1 1 1 1 1 2 4 8 16 32 0 1 2 3 4 5 Minitial
Fraction mass
remaining
# of half-lives
Minitial
 multiply by fraction
Mfinal
 multiply by denominator

4. half-lives # HL = ___time elapsed___ length of 1 half-life
[see Table N]