Question about Weak Nuclear Force

Simfish

Hi; I have a question: Does the weak nuclear force convey the decay undergone by radioisotopes or not? Is the decay of radioisotopes caused instead by the electromagnetic repulsion that overcomes the strong nuclear force? Also, what type of radioactivity is conveyed by the weak nuclear force? I know that beta decay is one; how about the other types of decay, including electron capture?

Oh; and another question: Do W-, W+, and Z0 bosons that convey the weak nuclear force have mass? Do the gluons that convey the strong nuclear force also convey mass? Also, does the strong nuclear force and the weak nuclear obey Pauli's exclusion principle? Or does Pauli's Exclusion Principle only occur for particles?

I am writing a summary of what the four forces are, for a 9th grade Physical Science assignment. While I will only need a one-sentence description of each force, I am compelled to write essays on all four forces, because this branch of physics really intrigues me. So can anyone please answer my questions? Thanks! =)

-Simfish