The isotope 208tl undergoes î² decay with a half-life of 3.1 min.
(a) what isotope is produced by the decay?
(b) how long will it take for 99.0% of a sample of pure 208tl to decay?
(c) what percentage of a sample of pure 208tl remains un-decayed after 1.0 h?

a. Pb 208

b. About 21.7 minutes

c. only a trace amount

Explanation:

It under goes beta decay.

There should be virtually nothing after an hour

the electrical  conductivity  of asolution  of an electrolyte is measured by determining the resistance of thesolution  between two flat or cylindrical electrodes separated by a fixed distance.

the answer is d.) potassium