Th-230(alpha)Ra-226.
230Th-----alpha particles-------226Ra
Po-216- -----------------> Pb-212
The nuclear reaction is: 232Th--------------- 228Ra + α
Alpha
There is no thallium-230 isotope.Also no thallium isotope decays by alpha decay, the unstable isotopes all decay either by K capture or beta decay.
Bismuth 213 => 2H4 + alpha
229Th-------alpha particle-----------225Ra
alpha
alpha
These are all phenomenons in nuclear physics.
Po-216- -----------------> Pb-212
daughter element
The nuclear reaction is: 232Th--------------- 228Ra + α
If radon-210 undergoes alpha decay, it will produce the alpha particle (which is a helium-4 nucleus) and polonium-206. The equation looks like this: 86210Ra => 24He + 84206Po You'll note that in the balanced nuclear equation, the atomic numbers, which are the subscripts, balance on both sides of the equation (86 = 2 + 84). The atomic masses, which are the superscripts, also balance on both sides of the equation (210 = 4 + 206).
The reaction is:U-238(alpha)Th-234
Alpha
lithium
224