Question

A radioactive nucleus undergoes a series of decays according to the sequence

\[\ce{X->[β] X1->[α] X2->[α]X3}\]

If the mass number and atomic number of X₃ are 172 and 69 respectively, what is the mass number and atomic number of X?

Answer 1

Mass no. of X = 180
Atomic no. of X = 72