Question

radioactive isotope half - life which radioactive isotope would take the least amount of time to become stable? rubidium - 91 58.4 seconds o rubidium - 91 iodine - 131 8 days o iodine - 131 cobalt - 60 5 years o cesium - 135 carbon - 14 5730 years o uranium - 238 cesium - 135 2.3 x 10^6 years uranium - 238 4.5 x 10^9 years

Explanation:

Step1: Compare half - lives

We compare the half - lives of all the given radioactive isotopes. Rubidium - 91 has a half - life of 58.4 seconds, Iodine - 131 has 8 days, Cobalt - 60 has 5 years, Carbon - 14 has 5730 years, Cesium - 135 has $2.3\times10^{6}$ years and Uranium - 238 has $4.5\times 10^{9}$ years.

Step2: Determine the shortest half - life

Since 58.4 seconds is the shortest time among all the half - lives, the isotope with this half - life will take the least amount of time to become stable.

Answer:

rubidium-91