After a series of alpha and beta decays, `._94Pu^(239)` becomes `._82Pb^(207)`. How many alpha and beta particles are emitted in the complete decay process?

Explanation

Here, parent nucleus is `._94Pu^(239)` and daugther nucleus is `._82Pb^(207)`
Decrease in mass number `=239-207=32`
Decrease in charge number `94-82=12`.
Let number of `alpha` particles emitted be x and number of `beta` particles emitted be y.
Now, one beta decay causes decreases in mass number by 4 and decrease in charge number by2. Again one beta decay causes increase in charge number by 1 and no change in mass number. Therefore, `x xx 4=32, x=32/4=8 and -yxx1+x xx 2=12`
`y=2x-12=2xx8-12=4`