Unstable Isotope Decay不稳定同位素的衰变

1、Unstable Isotope Decay,Half Life,A Note from Yesterday,Here is a decay series of an element. Elements will undergo alpha and beta decays.,Half-Life:,The time it takes for half of the radioactive nuclei in a given sample to undergo decay. Most all elements above 92 are radioactivebecause they dont fo

2、llow the band of stability (Linked to the P:N Ratio),Common Radioactive Isotopes,Isotope Half-Life Radiation Emitted Carbon-14 5,730 years b, g Radon-222 3.8 daysa Uranium-235 7.0 x 108 years a, g Uranium-238 4.46 x 109 years a,Nuclear Decay,While each radioisotope decays at a different rate they al

3、l decay at a constant rate. No environmental factors will change how fast their nucleus breaks apart.,Radioactive Half-Life,After one half life there is 1/2 of original sample left. After two half-lives, there will be 1/2 of the 1/2 = 1/4 the original sample. After three half-lives, there will be of

4、 the = 1/8 the original sample.,Example Problem #1,You have 100 g of radioactive C-14. The half-life of C-14 is 5730 years. How many grams are left after one half-life? How many grams are left after two half-lives? How much time has elapsed after 4 half lives?,Example Problem #2,A sample of 56.0 gra

5、ms of Radon are trapped in a sealed basement. The half-life of Radon is 4 days. How many grams of Radon are left after 24 days? How much is left after 8 days? Answer: 0.875 grams 14 grams,Remaining Nuclei vs Time,An Interesting Note,Lavoisier was most noted for? An additional piece to this “Law”is the word, “CHEMICAL” Unfortunately, this doesnt apply to NUCLEAR reactions Therefore