Which element has the lowest half-life?

Answer 1

Bismuth has recently been found to have a no stable isotope and has a half-life of 4.6 x 10^19 years. Also, the simple hydrogen atom (a single proton), is theorized to decay at a rate of 6.6 x 10^33 years. So far all tests to observe a proton decay have failed.

Answer 2

When talking about half-life, you should not ask about "elements" but about "isotopes". There is a great difference, for example, between hydrogen-2 (which is stable), and hydrogen-3 (which has a half-life of about 19 years). Same element, different isotopes.

The Wikipedia article, "List_of_isotopes_by_half-life", lists 6 isotopes with a half-life of less than a second; the shortest is Beryllium-8, with a half-life of 70 x 10-18 seconds (70 millionth of a millionth of a millionth second).

Answer 3

Any radioactive element has a half-life. Some examples are Polonium, Radon and Plutonium.

Answer 4

Francium has the lowest half-life among naturally occurring elements. Its most stable isotope, francium-223, has a half-life of only 22 minutes.