Radioactive Elements

Element Most Stable Isotope Half-life of Most Stable Istope Actinium Ac-227 21.77 years Thorium Th-229 7.54 x 104 years Protactinium Pa-231 3.28 x 104 years Uranium U-236 2.34 x 107 years
Subsequently, question is, how do you know which element is more radioactive? The two you asked about, iodine, atomic number 53, and barium, atomic number 56, both fall under the cutoff line for natural radioactivity. One way you can tell if an element is radioactive or not is with the use of a Geiger Counter, which measures the nuber of nuclei being degraded per minute.

Regarding this, what is the most dangerous element?

Plutonium: A History of the Worlds Most Dangerous Element.

Why is radioactivity dangerous?

Ionizing radiationRadiation with so much energy it can knock electrons out of atoms. Ionizing radiation can affect the atoms in living things, so it poses a health risk by damaging tissue and DNA in genes. has sufficient energy to affect the atoms in living cells and thereby damage their genetic material (DNA).