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?

Ican determine the molar mass of an element by looking on the under the atomic mass for the element. for example the molar mass of phosphorus is 30.974 grams/mole. avogadro’s number tells me the amount of representative particles in 1 mole of any substance. this means 12.011 gram sample of carbon and a 32.0 gram sample of sulfur have the same number of atoms.