How do I figure out what kind of radiation is emitted in a nuclear reaction?

For example, I have this problem: 92 238 U -%26gt; A + 2 4 He



I figured A had to be 90 234 Th, but the second part of the question is: "describe the types of radiation given off in the series". I have 11 of these reactions to work on, and I'm confused. Any help is appreciated.How do I figure out what kind of radiation is emitted in a nuclear reaction?
TRy to learn from here

http://www.ameriphysics.com/How do I figure out what kind of radiation is emitted in a nuclear reaction?
The best way to figure out what kind of radiation is emitted is to dip your index finger into the nuclear material and then taste it