This is a list of radioactive nuclides (sometimes also called isotopes), ordered by half-life from shortest to longest, in seconds, minutes, hours, days and years.
Current methods make it difficult to measure half-lives between approximately 10−19 and 10−10 seconds.
[1] Twenty-three yoctoseconds is the time needed to traverse a 7-femtometre distance at the speed of light—around the diameter of a large atomic nucleus.
The half-life of tellurium-128 is over 160 trillion times greater than the age of the universe, which is 4.35×1017 seconds.
[7]