Nuclear physics question

A single 212Po nucleus, initially at rest, emits an alpha particle as it decays into a 208Pb nucleus. There are no other decay products, and the kinetic energy of the alpha particle is measured to be $1.407 × 10-12 J$. What is the total amount of nuclear potential energy, in joules, that was released in this process? 

$PE_{nuclear} = ?J$

What is the difference between the original mass of the 212Po nucleus and the total mass of the fragments after the decay?

$Delta M = ?kg$


$PE = Ek +m(\alpha)*c^2$

$m (4,2He) =6.644*10^-27 kg (=4.001 amu)$

$PE = 1.407*10^{-12} +6.644*10^-{27}*9*10^{16} =5.9937*10^{-10} J$

Mass defect is

$m(208Pb) =207.9766 amu$   (

$m(212Po) =211.989 amu$  (

$\Delta(M) = 211.989 -207.9766-4.001 =0.0114 amu =0.0114*1.66*10^-{27} =1.892*10^{-29} kg$