question_answer

Explain how radioactive nuclei can emit \[\beta \] -particles even though atomic nuclei do not contain these particles. Hence explain why the mass number of a radioactive nuclide does not change during \[\beta \] -decay.

Answer:

                A neutron from the nucleus decays to emit a proton, an electron and an antineutrino. The electron is emitted in the form of a \[\beta \] -particle. \[_{0}^{1}n\to _{1}^{1}p+_{-1}^{0}e+\overset{-}{\mathop{v}}\,\] During \[\beta \] -decay, a neutron simply changes into a proton i.e., only the character of nucleon changes. Hence the mass number of a radioactive nuclide does not change during a\[\beta \]-decay.