Isotope decay via alpha and beta particle emissions

[greg_rack]

Homework Statement

The radioactive isotope X becomes the stable isotope Y after a succession of decays involving only the emission of alpha and beta (β–) particles.
During the decay of one nucleus from X to Y, a total of seven particles are emitted. It is known that more of these particles are alpha particles than beta particles.
The atomic number of X is Z and the mass number of X is A.
Which row in the table(attached to the "solution" section) could give the atomic number and the mass number of Y?

Relevant Equations

None

This problem really confused me, since I can't get the link between particles emitted(alpha and beta, but which are the differences between those?) and changes in mass and atomic number of the isotope.
For this one, I can't really show you my attempt since there ain't one...

 

[CPW]

What does your textbook say happens during alpha decay? (How does the atomic number Z and the mass number A change?)

What does your textbook say happens during beta minus decay? (How does the atomic number Z and the mass number A change?)