Explain radioactive decay and describe alpha, beta and gamma emission.

Solution & explanation

Unstable nuclei transform spontaneously and randomly; a population follows statistical decay. Alpha emission lowers A by 4 and Z by 2. Beta-minus converts a neutron to a proton with electron and antineutrino emission, raising Z by 1 while A stays fixed. Gamma emission lowers excitation energy without changing A or Z. Individual decay times cannot be predicted.