¹²⁸Te undergoes an extremely rare form of radioactive decay know as double beta decay:

This is an extremely low probability event; its half-life of 2.2 × 10²⁴ years is among the longest half-lives that have been determined. Estimate the activity in a 128-g (1 mol) sample of ¹²⁸Te. How many ¹²⁸Te atoms in such a 1-mol sample would decay in a day?

Transcribed Image Text:

128 Te 138Xe + 2 _B + 2 +