devarshi-dt-logo

Question:

In a radioactive decay chain, 23290Th nucleus decays to 21282Pb nucleus. Let Nα and Nβ be the number of α and β− particles respectively, emitted in this decay process. Which of the following statements is (are) true?

Nβ=2

Nβ=4

Nα=5

Nα=6

Solution:

The correct options are Nα=5 and Nβ=2
23290Th has converted into 21282Pb
Change in mass number (A) = 20
∴ no of α particle = 20/4 = 5
Due to 5 α particle, z will change by 10 unit. Since given change is 8, therefore no. of the beta particle is 10 − 8 = 2