Beta Decay Proton: Ion Formation?

[quantumlight]

if beta decay is the result of ejection of electron from the decay of a neutron into a proton and electron does that mean the the resultant product nucleus would be an ion since it would have an extra proton? and same thing when a positron is formed from decay of proton?

 

[Astronuc]

The atom with an extra proton is then a new element, and it will attract a nearby electron. A beta particle will slow down, so the material overall will remain electrically neutral. Electrons will be attracted to a net positive charge until the beta particle is absorbed into a nearby atom.

Similarly, in positron emission, the atom gives up an atomic electron. The positron slows down in the material and ultimately interacts with an electron and the two are annihilated, whereby they are transformed into gamma-rays (photons). Thus charge balance is maintained.

 

[quantumlight]

i c but another thing i don't understand about beta decay is why heavier +84 atoms like thorium undergo beta decay when the stability belt says it should undergo alpha decay

 

[Meir Achuz]

1. The atom immediatly following beta decay is a + ion. Depending on the chemistry, etc. it will eventually neutralize by picking up an electron.

2. Beta decay occurs if a nucleus is too far above or below the n-p stability line. Beta decay is usually faster than alpha decay (no tunneling), so if it can happen, it does, before alpha decay.

 

[Astronuc]

Adding to what Meir Achuz wrote, you might find these useful:

http://hyperphysics.phy-astr.gsu.edu/Hbase/nuclear/radser.html
http://hyperphysics.phy-astr.gsu.edu/Hbase/nuclear/rdpath.html

If one looks at the decay series, one will observe that the isotopes of Th general decay by alpha emission. However, Ac-227 can decay either by beta to Th-227, or by alpha emission to Fr-223. Fr-223, At-219, Po-215 and Bi-211 can also decay by beta or alpha emission. Po-216 and Bi-212 also can undergo beta or alpha decay.

One could do a calculation of the Q-value of beta and alpha decays to see which seems more advantageous in terms of dumping eneryg.

Also look at - http://www.nndc.bnl.gov/chart/ - and browse the heavy upper right corner. Look for general trends in decay mode as a function of half-life and neutron/proton ratio. Some transuranics undergo spontaneous fission (SF). On the upper side of the population one observes more alpha decay and electron capture, while on the lower side of the population, one observes more beta decay. Out past Lr, one sees mostly SF or alpha decay.

Another good resource is - http://wwwndc.tokai-sc.jaea.go.jp/CN04/index.html

 

[quantumlight]

thnx i'll go read thsoe up