Beta plus decay: mass balance?

  • Thread starter Chem.Stud.
  • Start date
  • #1
27
2
Hi:

I am taking a radiochemistry class, and I am confused by beta plus decay.

(1) p --> n + positron + electron-neutrino

The mass of a proton is less than the mass of a neutron. In addition, the neutrino has mass as does the positron.

(2) E = mc2

There must be come sort of balance, must there not? Mass cannot be created unless energy is consumed. So where does the nuclei get the energy from to convert a single proton into three different particles, one of which has a larger mass than the proton itself?

I hope I have made my confusion understandable. Also, my macbook would not let me use the greek characters or sub- and superscript.

Sincerely,
Anders
 

Answers and Replies

  • #2
SteamKing
Staff Emeritus
Science Advisor
Homework Helper
12,796
1,668
The beta-plus decay cannot occur in a single proton due to the need for energy to be supplied from some external source.

See: http://en.wikipedia.org/wiki/Beta_decay

In heavier nuclei, beta-plus decay can occur if the original nucleus has a higher binding energy than the nucleus which remains after the emission of the beta-plus particle.
 
  • #3
27
2
Ahh, that makes sense. Thank you for your help.
 

Related Threads on Beta plus decay: mass balance?

  • Last Post
Replies
5
Views
12K
  • Last Post
Replies
8
Views
826
  • Last Post
Replies
6
Views
2K
Replies
4
Views
2K
Replies
1
Views
2K
  • Last Post
Replies
8
Views
7K
Replies
2
Views
716
Replies
1
Views
3K
Replies
8
Views
1K
  • Last Post
Replies
4
Views
867
Top