Question: what is the most radioactive material on the periodic table

Alexander de Bruin answered on 21 Mar 2025:

It depends how you define “radioactive”! Polonium is thought to be the most radioactive natural element and it glows blue because of the interaction of the radiation it emits with the air surrounding the lump of metal. Other, faster decaying (decay = the way materials emit radiation), elements have been made in labs – Nobelium, Lawrencium, and Element 118.