Beta Decay expels a electron & antineutrino from the nucleus?

Question

where did the electron come from,didn't think any electrons were in the nucleus?

Answer 1

No, beta decay is a product of the weak nuclear force, and what happens is that a Neutron decays into a Proton. When that happens, an electron and an anti-neutrino pop into existence to preserve energy and momentum (remember those laws?)

Remember that there are other constituent parts to the Proton, i.e. up and down quarks. Beta decay converts a down quark to an up quark, hence the extra particles that spin off, i.e. an electron and an anti-neutrino.

You are right, there are no electrons in the nucleus, BUT when particles decay they break down into the weird constituent parts I've mentioned.

anyway, take a look at the link below if you want...

Answer 2

Keep in mind that gamma rays can collide and form an electron and positron. The electron did not reside in the nucleus, it was newly formed. A neutron is converted into a proton by emitting an electron and anti-neutrino.