Conservations in nuclear reactions

[Fiona Rozario]

Is the atomic number and mass number conserved in nuclear decays?

 

[vanhees71]

No! Take $\beta$ decay, where within a nucleus a neutron decays to a proton, electron, and antielectron neutrino. The daughter nucleus has the same number of nucleons $A'=A$ but $Z'=Z+1$.

For $\alpha$ decay a nucleus emits a $_2^4\mathrm{He}$ nucleus, i.e., the daughter nucleus has $A'=A-4$ and $Z'=Z-2$.

https://en.wikipedia.org/wiki/Radioactive_decay#Types_of_decay

 

[Vanadium 50]

What decays have you looked it? Are the atomic number and mass number conserved in those decays?

 

[Fervent Freyja]

Usually not, but that depends upon the type of decay...

 

[Fiona Rozario]

So mass number is conserved but not atomic number...

 

[mfb]

So mass number is conserved but not atomic number...

Right (assuming you count all invovled particles, e.g. including the alpha nucleus in an alpha decay).

The conservation of the sum of mass numbers is equivalent to baryon number conservation. While it is expected that there are processes changing it, it has never been observed.

 

[Fervent Freyja]

In the case of gamma decay, both are conserved (most of the time).