The following are alpha emitters. what are the reactions produced in each case?

Question

Uranium-238
Thorium-230
Uranium-235
Radon-222

Answer 1

An alpha particle is a helium nucleus and contains 2 protons and 2 neutrons. Thus the mass number is reduced by 4 and the atomic number is reduced by 2.

U238 ----> Th 234

U 235 -----> Th 231

Rn 222 -----> Po 218

Th 230 ------> Ra 226

See
http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/radser.html#c3