Nuclear charge radioactive series

The Uranium Series o Radioactive Disintegrations. When an alpha particle (He++) is emitted by an atomic nucleus the nuclear charge decreases by two units the element hence is transmuted into the element two columns to the left in the periodic table. Its mass number (atomic weight) decreases by 4, the mass of the alpha particle. 

We use X to indicate any element defined by its nuclear charge, Z and Z-2 in this equation. Examples are given in Ch. 1, and can be found e.g. in the natural radioactive decay series, see next chapter. 

The great majority of nuclei are unstable and undergo various types of radioactive decay a decay, p decay, positron emission, electron capture, and -y emission. In nuclear reactions, total mass number (A) and total charge (Z) must be balanced. A plot of number of neutrons (N) versus number of protons (Z) for all nuclei shows a narrow band of stable nuclei. To become more stable the type of decay can often be predicted from the N/Z ratio of the unstable nucleus. Certain heavy nuclei undergo a series of decays to reach stabiity. 

AU nuclei with 84 or more protons are radioactive. Heavy nudei gain stability by a series of nudear disintegrations leading to a stable nucleus. Nuclear transmutations are nuclear reactions that are induced by bombardment of a nucleus by a neutron or accelerated charged partide, such as an alpha partide. 

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