Question

A radioactive isotope M decays by emitting two alpha and a beta particle to form ²⁰⁶ ₈₃Y.

1. What was the atomic number of M 
2. After 224 days 1/16 of mass of M remained. Determine the half-life of M.

Answer 1

1. Atomic number = 83 + 4 -1 = 86
2.   
   • 
     There are 4 t_½ 
     4 t_½ = 224 
     t_½ = 56 days