No, not all elements with an atomic number greater than one are radioactive. Radioactivity refers to the spontaneous emission of radiation from the atomic nucleus. While some elements with higher atomic numbers (such as uranium, plutonium, or radium) are indeed radioactive, many elements with atomic numbers greater than one are stable and non-radioactive.
For example, elements like carbon (atomic number 6), oxygen (atomic number 8), iron (atomic number 26), and gold (atomic number 79) are stable and not considered radioactive. These elements have stable atomic nuclei that do not undergo spontaneous decay.
The stability or radioactivity of an element is determined by the balance between the forces within the atomic nucleus. Factors such as the number of protons, neutrons, and the nuclear binding forces influence whether an element is stable or radioactive. While some isotopes of these stable elements may be radioactive, the stable isotopes are generally more common and dominant in nature.