Question

Modern Physics: Solid State and Nuclear Physics

Promethium (Pm) is a very interesting element because it has no long lived isotopes, and at any given time there is only estimated to be approximately 500 g distributed through the crust of the Earth.

a. Write the possible decay reactions for ¹⁴⁷Pm.

b. Calculate the disintegration energy for each reaction, and from this determine the method of decay.

c. Is the resulting daughter nucleus stable?

Answer 1

given Pm 147
the disintegration reactions of this nucleus can be as under:

147 Pm -> beta decay -> 147 Sm + e
mass of electron me = 9.1*10^-31 kg = 0.00054858 u
mass of 147 Sm = 146.9148979 u
mass of 147 Pm = 146.9151385 u
mass deficit = 0.00030798 u
hecne energy produced = dm*c^2 = dm*1.6*10^-27 kg *c^2 = 0.277182 MeV

a. the Pm 147 nucleuys decays only whith beta -ve decay emitting an electreon in the process

b. the energy has been derived above

c. the resulting nucleus 147Sm is stable