Question

the table shows a list of radioisotopes and their half - lives.
the radioisotope that has the longest half - life is the best to use in powering planet and space exploration vehicles because they can travel farther. which radioisotope is the best to use?

Explanation:

Step1: Compare half - lives

Compare the half - lives of all radioisotopes. Lithium - 5 has a half - life of \(3\times10^{-22}\text{ s}\), Polonium - 211 has \(0.156\text{ s}\), Barium - 139 has \(82.7\text{ min}\), Uranium - 240 has \(14.1\text{ h}\), Bismuth - 210 has \(5.012\text{ days}\), Uranium - 232 has \(68.9\text{ years}\), Carbon - 14 has \(5730\text{ years}\), Plutonium - 239 has \(24065\text{ years}\), Seaborgium - 10 has \(1.6\times10^{6}\text{ years}\), Uranium - 238 has \(4.5\times 10^{9}\text{ years}\).

Step2: Identify the longest half - life

Among these values, \(4.5\times 10^{9}\text{ years}\) (Uranium - 238) is not in the options. Among the given options (Lithium - 5, Uranium - 240, Plutonium - 239, Carbon - 14), comparing \(3\times10^{-22}\text{ s}\) (Lithium - 5), \(14.1\text{ h}\) (Uranium - 240), \(24065\text{ years}\) (Plutonium - 239), \(5730\text{ years}\) (Carbon - 14).
Since \(24065\text{ years}>5730\text{ years}>14.1\text{ h}>3\times10^{-22}\text{ s}\)

Answer:

Plutonium - 239