Predicting radioactive decay (1 Viewer)

[fysicz]

say i give you a certain radioactive isotope and i want to predict whether it emits alpha or beta decay, emits a positron or accepts?

eg. Fe-53 or Th-144

I know that there is a trend; that heavier elements tend to emit beta particles however, that isn't always the case.

can anyone help?

 

[insert-username]

say i give you a certain radioactive isotope and i want to predict whether it emits alpha or beta decay, emits a positron or accepts?

eg. Fe-53 or Th-144

I know that there is a trend; that heavier elements tend to emit beta particles however, that isn't always the case.

can anyone help?

If the number of protons is above 83, the element generally emits alpha particles. This is because the nucleus is too big for the strong nuclear forces to hold the atom together.

If there are too many neutrons (neutron to proton ratio greater than 1:1 for low molecular weight elements, or greater than 1.6:1 for high molecular weight elements), then the element will undergo beta decay, often accompanied by gamma emmission.

Positron decay is not in the HSC syllabus, so you don't need to worry too much about it.

By the way, Th-144 doesn't exist. Thorium has 90 proton and an average molecular mass of 232.


I_F

 

[bmc]

well i'm not sure that there is a trend apart from what you've already said... i think you have to lok at the cases individually and perhaps just learn the more common ones (like americium-241 emits alpha, etc.). if you're asking with regard to the hsc, i think it's way out of the syllabus and you probably wouldn't be asked to predict what kind of decay would be emitted... at least, if you do, our school didn't say so!! =)

yes i never came across having to predict what type of decay occurs. In all the past papers ive seen the question always stated what type pf decay. And i never came across positrons in chem.