Question

Which of the following series of radioactive decays would convert Pb-214 to Pb-210?

A. Beta, alpha, positron

B. Alpha, positron, positron

C. None of the other choices are correct.

D. Alpha, alpha, electron capture

E. Beta, beta, alpha

Answer 1

To convert Pb-214 to Pb-210, one would need to undergo two beta decays, which increase the atomic number while keeping the mass number the same, followed by an alpha decay, which decreases both the mass number and atomic number, resulting in the correct sequence of beta, beta, alpha.

Step-by-step explanation:

The series of radioactive decays that would convert Pb-214 to Pb-210 involves two beta (β) decays followed by one alpha (α) decay. This sequence can be described as the following:

• Beta decay: This involves the conversion of a neutron into a proton, with the emission of an electron (β- particle) and an antineutrino. As a result, the mass number remains the same, but the atomic number increases by one.
• Alpha decay: This type of decay emits an alpha particle, which is essentially a helium nucleus consisting of two protons and two neutrons. Consequently, the mass number decreases by four and the atomic number decreases by two.

Through beta decay, Pb-214 (atomic number 82) would first decay to Bi-214 (atomic number 83), followed by another beta decay to Po-214 (atomic number 84). Finally, through alpha decay, Po-214 would decay to Pb-210 (atomic number 82). Therefore, the correct sequence of decay is beta, beta, alpha (E).