Question

Uranium-234 is unstable and undergoes two subsequent alpha emissions. What is the resulting nuclide from this transformation?

Answer 1

alpha decay produces an alpha particle, which looks like\[^4_2 \alpha \space \text {or} \space ^4_2He\]
balancing nuclear reactions is almost the same as balancing "normal" chemical reactions, but we have to be certain to balance not just total mass, but total atomic number, as well. So, in this case, if U-234 undergoes alpha decay once, it should get you
\[^{234}_{92}U \rightarrow ^4_2\alpha + \space ??\] What mass will the remaining atom have? How many protons will it have?

Answer 2

If that particle undergoes alpha-decay again, what is the particle left over?