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need step by step help please thanks 10 Physicists thought for a long time that

ID: 2030976 • Letter: N

Question

need step by step help please thanks

10 Physicists thought for a long time that bismuth-209 was the heaviest stable isotope. (Very heavy elements decay by alpha emis- sion because of the strong electrical repulsion of all their protons.) However, a 2003 paper by Marcillac et al. describes an experiment in which bismuth-209 lost its claim to fame it actually undergoes alpha decay with a half life of 1.9 x 1019 years. (a) After the alpha particle is emitted, what is the isotope left over? (b) Compare the half-life to the age of the universe, which is about 14 billion years (c) A tablespoon of Pepto-Bismol contains about 4 x 1020 bismuth- 209 atoms Once you've swallowed it, how much time will it take on the average, before the first atomic decay?

Explanation / Answer

10

a)

The isotope left over is thallium-205

b)

T1/2 = half life = 1.9 x 1019 yrs

T = age of universe = 14 billion yrs = 1.4 x 1010 yrs

ratio = T1/2 /T = (1.9 x 1019)/(1.4 x 1010) = 1.4 x 109