Which radioactive isotope would have the longer half- life 15 O or 19 O? (Given rate constants for 15 O and 19 O are 5.63x 10 -3 s -1 and k = 2.38 x 10 -2 s -1 respectively.)
- 15 O
- 19 O
- Both will have the same half-life
- None of the above, information given is insufficient
a. 15 O
The rate constant for the decay of O-15 is less than that for O-19 . Therefore ,the rate of decay of O-15 will be slower and will have a longer half life .