A nucleus with mass number A and atomic number Z is represented as (A, Z).
The column “Daughter nucleus” indicates the difference between the new nucleus and the original nucleus.
Radioactive decay occurs when an unstable atomic nucleus loses energy by emitting energy in the form of emitted particles or electromagnetic waves, called radiation.
Isotopes are atoms of the same element (thereby having the same number of protons) which differ in the number of neutrons in their nucleus.
Over four years, working under poor conditions and spending their own funds, the Curies processed more than a ton of uranium ore to isolate a mere gram of radium salt.