Alpha decay (two protons and two neutrons) changes the mass number of the element by -4 and the atomic number by -2 so the remaining nucleus will be \(_{90}^{234}?\). A periodic table shows that ...

^{4}\textrm{He}\) When a radioactive atom emits an alpha particle the mass number decreases by four and the atomic number drops by two. Here is the equation for the alpha decay of radon-219 into ...

obeys the decay differential equation: \begin{equation ... Plutonium-239 is part of the highly radioactive waste that nuclear power plans produce. The half-life of plutonium-239 is 24,110 years.