Radiation (Beta, Electron Capture) and Decay Constant?

Question

Our chemistry class is going over radiation, and I just have a few questions.

For Beta decay, does a neutron turn into a proton and electron, and then the electron given off as a Beta particle? And if so, how does this happen?
Also, how does a proton and electron turn into a neutron in Electron Capture?

And what is the decay constant?
Also, for the equation: Rate = k[A] where k=decay constant and [A] is the amount of material, what can be plugged in for the rate? If half-life is plugged into for the rate, does the equation work?

Answer 1

It is thought that the neutron is made of an electron and a proton. So in beta decay they separate and an electron shoots out of the nucleus as beta decay and the atomic number goes up one.
The neutrons are good separaters of all the positive protons in the nucleus, so isotopes of large atoms that have fewer neutrons seem to be the less stable isotopes.

Answer 2

1. a. Yes it does b. Yes it does c. I do not know

2. I do not know

You have asked how these decay modes happen and why they happen in that way. If any one can explain why beta-minus decay happens and electron capture does not, or why electron capture happens with Th-201 and in other nuclei not, I should be very glad to know the explanation.

Rate = k[A] = d[A]/dt

One cannot plug the half-life intothe rate equation.