Homework Question - Beta and Alpha decay

[LotusTK]

Hi, i am new here. Thought it would be good to sign up as i have just started hitting the books in preparation for my AS Level exams. So this is my first question.

I think i may have done this question correctly, but i was just seeing what other people think as i am not 100% sure about it.

Question:

A nucleus of the radioactive isotope of bismuth Bi (213) and (83) emits a beta particle, then an alpha particle, then another beta particle before it becomes stable.

a) Show that the stable nucleus formed is a Bismuth isotope

My Attempt at it

Bi (213) (83) → Bi (213) (84) I have added one to the proton number, because in beta decay, a neutron turns into a proton, so the nucleon number remains the same, but the proton number goes up by 1.

Then for Alpha, it becomes Bi (209) (82). I have taken 4 from the nucleon number and 2 from the proton number because an alpha particle consists of 2 protons and 2 neutrons.

Then after the second beta decay i ended up with Bi (209) (83).

Is this correct?

Thanks for your help.

 

[Curious3141]

Looks good, but I'm not sure whether they're expecting you to write step by step proper nuclear reactions (including the electrons and antineutrinos and the alpha particles ).

 

[mfb]

I agree with the numbers, but the symbols of the intermediate nuclei are not "Bi".

 

[LotusTK]

Thanks for the replies.

Curious3141, i don't think you do have to, but i know how to if i were to be asked in an exam. Just write B (0) (-1) add the anti neutrino (the v with the line above it) to the beta decay, and fore alpha, write the alpha symbol with (4) (2).

mfb, I just used "Bi" as that was the element quoted in the question. I know that the elements that are formed inbetween are not "Bi".

Expect me to ask more questions later on, as i will be starting to revise Leptons and all of that stuff that I am really weak with. :D

 

[Curious3141]

Thanks for the replies.

Curious3141, i don't think you do have to, but i know how to if i were to be asked in an exam. Just write B (0) (-1) add the anti neutrino (the v with the line above it) to the beta decay, and fore alpha, write the alpha symbol with (4) (2).

mfb, I just used "Bi" as that was the element quoted in the question. I know that the elements that are formed inbetween are not "Bi".

Expect me to ask more questions later on, as i will be starting to revise Leptons and all of that stuff that I am really weak with. :D

No, but mfb is right - in writing that way, it's wrong. It's OK to omit the symbol entirely (if you're just writing informally), but to actually put "Bi" there is wrong.

 

[LotusTK]

The proton number?

 

[Curious3141]

The proton number?

Steamking's post (that you're replying to) has vanished. But you're correct. I prefer to refer to it as the atomic number, because that's a good reminder that this is the number that determines what atom it is.