A radioactive isotope has a half-life of 2 minutes. How many total minutes will it take for 100-g of the isotope to get to just 6.25-g remaining

It would take 12 minutes.

8 minutes

Explanation:

G(g)                 T(min)

100 0

502

25 4

12.5    6

6.25 8

     another    way:

100/6.25 = 16

  16 = 2⁴       ( 4 half lives)    

Each half life is 2 minutes

so 4 half lives will be 8 minutes

i think it's c. if you look search electronic symbol on google and then click on wiki it shows you a

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