Question

What is the effect on the atomic mass and the atomic number of a radioactive element, after the emission of an α-particle?

Answer 1

During the emission of an α-particle from the nucleus of a radioactive element, its atomic mass decreases by 4 and the atomic number also decreases by 2. If _ZX^A represents a radioactive element having atomic mass A and atomic number Z, then:

\[\ce{_ZX^A ->[α-particles][_2He^4] _{Z-2}Y^{A-4}}\]