Final answer:
The question focuses on the radioactive decay behavior of an isotope with an atomic mass of 150.99. It involves concepts like beta decay, half-life, and the fact that the mass of a radioactive isotope decreases as it emits particles during decay.
Step-by-step explanation:
Understanding the concept of radioactive decay involves exploring the behavior of unstable isotopes as they lose energy by emitting radiation. An example is an isotope represented by 151 X with an atomic mass of 150.99 undergoing beta decay. Beta decay refers to the process by which a neutron in the nucleus of an atom converts into a proton and a beta particle (electron) is emitted. This results in an increase in the atomic number by one while maintaining the same mass number since a proton and a neutron have nearly the same mass.
Radioactive decay is a spontaneous process where an unstable atomic nucleus loses energy by radiation. A characteristic feature of radioactive decay is the half-life, which is the time required for half of the radioactive nuclei in a sample to decay. The half-life is constant for a given isotope and is independent of the starting amount of material. Therefore, after each half-life period passes, the amount of radioactive isotope and its associated radioactivity reduces by half, following a predictable decay pattern. Furthermore, isotopes do not maintain a constant mass when undergoing radioactive decay, as this process involves the emission of particles which carry away mass and energy.