Some of these isotopes have a half-life of a few seconds or less, while others last and last
In the periodic table, most of the elements have at least one stable form. Others, however, have only unstable forms, all of which break down into various elements releasing radiation and turning them into a stable form. The fixed time for radioactive decay is called the half-life of an element. This is the time required to cut a sample of an item in half.
In general, the elements after uranium have a shorter lifespan, the longer they are in the periodic table – the higher their atomic number. The half-life of unstable elements varies from about 30 orders of resistance. For comparison: the diameter of the Milky Way is about 30 orders of magnitude greater than the width of a DNA helix.
The graph below shows the time it takes for the longest isotope – a shape with the same number of protons but a different number of neutrons – each of the unstable elements to decompose. (These half-lives are not exact numbers; there is an uncertainty associated with each other.) Even plotted on a logarithmic scale, the distance between points on the graph representing more periods of time, as the half-life increases, bismuth, the unstable element with the longest life, is not shown in the graphs.
Do all future elements discovered have a shorter half-life earlier? Scientists are not sure. They expect a theoretical “island of stability” where the half-life will amplify the trend. These items may take a few seconds or a day. No one knows what properties they will have or if these elements will help scientists learn more about how the atom – and therefore everything – comes together. And so researchers continue to destroy atoms and hope to paddle near the legendary coast of the island.
This graphic plots the life spans, or half-lives, of the periodic table’s unstable elements (blue) on a logarithmic scale. Data for each element’s longest-lived form, or isotope, are included, along with familiar comparisons (green).