Question

In the uranium radioactive series, the initial nucleus is \[\ce{_92U^238}\] and that the final nucleus is \[\ce{_82U^206}\]. When uranium nucleus decays to lead, the number of α particles and β particles emitted are ______.

Options

• 8α, 6β

• 6α, 7β

• 6α, 8β

• 4α, 3β

Answer 1

In the uranium radioactive series, the initial nucleus is \[\ce{_92U^238}\] and that the final nucleus is \[\ce{_82U^206}\]. When uranium nucleus decays to lead, the number of α particles and β particles emitted are 8α, 6β.

Explanation:

Let no. of α-particles emitted be x and no. of β particles emitted be y. 

Diff. in mass no.:

4x = 238 − 206 

4x = 32 

⇒ x = 8

Diff. in atomic no.:

2x − 1y = 92 − 82

2(8) − 1y = 10

16 − y = 10

⇒ y = 6