What commonly occurs during the decay of a radioactive isotope?

When a radioactive isotope undergoes decay, the nucleus of the atom experiences a transformation that often involves changes to its structure. This process can include the emission of particles such as alpha or beta particles, resulting in a change in the number of protons and neutrons within the nucleus. As the isotope decays, it may transform into a different element or a different isotope of the same element, indicating a change in the nucleus's structural configuration.

The options that involve the addition of neutrons or the loss of protons do not accurately describe the general process of radioactive decay. While electrons are occasionally emitted through processes like beta decay, the primary and most defining feature of radioactive decay is the alteration of the nucleus’s structure itself, leading to a new identity for the atom after decay. This structural transformation is a key concept in understanding how radioactive isotopes behave and change over time.