Yes, the atomic number of an element does not change during radioactive decay. When an isotope of an element undergoes radioactive decay, it transforms into a different isotope or a different element altogether. However, the atomic number remains the same because it is determined by the number of protons in the nucleus. The decay process may involve the emission of alpha particles, beta particles, or gamma rays, but the total number of protons in the nucleus, and therefore the atomic number, remains unchanged. In the case of polonium-211, which is a radioactive isotope of polonium, the atomic number remains 84, indicating that it is still an element with 84 protons in its nucleus even after undergoing decay.