chemistry help!!!!!!?

Question

my homework is to complete a crossword puzzle
and these were the hints,
1) Radioactive rocks have this property
(# of letters : 14)
2) element made when boron and a neutron collide
(# of letters: 9)
3) The parent atom from which astatine and a beta particle are produced
(# of letters:8)

Answer 1

More hints (I don't give out answers, but help people get there)

1) I think this is a word that means breaking down. Strictly speaking it isn't the rock that does it but the radioactive elements inside.

2) nine letters, too long to be the ordinary name of any element in that part of the periodic table. But there is one element which has an isotope with a special name, and that could be formed by the neutron reacting with the boron nucleus

3) When an element emits a beta particle, the atomic number goes up by one (why?). So this should tell you the answer here.