Answer: 8 alpha particles
Explanation:-
Alpha decay : When a larger nuclei decays into smaller nuclei by releasing alpha particle. In this process, the mass number and atomic number is reduced by 4 and 2 units respectively.
General representation of alpha decay :
[tex]_Z^A\textrm{X}\rightarrow _{Z-2}^{A-4}Y+_2^4\alpha[/tex]
[tex]_{92}^{238}\textrm{U}\rightarrow _{82}^{26}\textrm{Pb}+_2^4\textrm{He}[/tex]
As the mass should remain same after the decay, we can use:
238=206+(4x)
Solving for x, we get:
x= 8.
Thus 8 alpha particles are emitted in the series of radioactive decay events from a U-238 nucleus to a Pb-206 nucleus.
