the half life of I -137 is 8.07 days. if 24 grams are left after 40.35 days, how many grams were in the original sample?

768g

Explanation:

We can use to formula . Here, N(A) is the final amount. N0 is the initial amount. t is the time elapsed, and is the half life. Plugging in, we get the answer above.

atomic mass = 39

number of neutrons = 20

number of protons= 19

electronic configuration = 1s2 2s2 2p6 3s2 3p6 4s1

the number of electron in first shell = 2

number of electrons in n=3 shell = 8