In a series of decays (hypothetical), the nuclide Ra-227 beomes Pb-203. How many alphas and how many betas are emitted in this series? Give two answers: first, give the number of alpha decays; then, the number of beta decays.
I know that there are 6 alpha decays happening. I just do not get the beta decay part.
To determine the number of alpha and beta decays in the given series, we need to understand the decay process and use the concept of radioactive decay chains.
In a decay chain, each decay process leads to the formation of a different nuclide until a stable nuclide is reached. The decay can occur through the emission of alpha particles, beta particles, or other particles such as gamma rays.
In the case of Ra-227 decaying to Pb-203, let's break down the decay process step by step:
1. Ra-227 (parent nuclide) undergoes alpha decay, emitting an alpha particle (2 protons and 2 neutrons), resulting in Rn-223.
- Alpha decay: Ra-227 -> Rn-223 + alpha particle
- Count: 1 alpha decay
2. Rn-223 (daughter nuclide) undergoes alpha decay, emitting another alpha particle, resulting in Po-219.
- Alpha decay: Rn-223 -> Po-219 + alpha particle
- Count: 2 alpha decays
3. Po-219 undergoes alpha decay, emitting yet another alpha particle, resulting in Pb-215.
- Alpha decay: Po-219 -> Pb-215 + alpha particle
- Count: 3 alpha decays
4. Pb-215 undergoes beta-minus decay, emitting a beta particle (an electron) and transforming into Bi-215.
- Beta-minus decay: Pb-215 -> Bi-215 + beta particle
- Count: 1 beta decay
5. Bi-215 undergoes alpha decay, emitting an alpha particle and transforming into Tl-211.
- Alpha decay: Bi-215 -> Tl-211 + alpha particle
- Count: 4 alpha decays
6. Tl-211 undergoes beta-minus decay, emitting a beta particle and transforming into Pb-211.
- Beta-minus decay: Tl-211 -> Pb-211 + beta particle
- Count: 2 beta decays
7. Pb-211 undergoes beta-minus decay, emitting a beta particle and transforming into Bi-211.
- Beta-minus decay: Pb-211 -> Bi-211 + beta particle
- Count: 3 beta decays
8. Bi-211 undergoes alpha decay, emitting an alpha particle and transforming into Tl-207.
- Alpha decay: Bi-211 -> Tl-207 + alpha particle
- Count: 5 alpha decays
9. Tl-207 undergoes beta-minus decay, emitting a beta particle and transforming into Pb-207 (stable nuclide).
- Beta-minus decay: Tl-207 -> Pb-207 + beta particle
- Count: 4 beta decays
Therefore, in the series of decays, there are 6 alpha decays and 4 beta decays.
I hope this clarifies the process and answers your question!