Search results
Results from the WOW.Com Content Network
The tables of elements are sorted in order of decreasing number of nuclides associated with each element. (For a list sorted entirely in terms of half-lives of nuclides, with mixing of elements, see List of nuclides.) Stable and unstable (marked decays) nuclides are given, with symbols for unstable (radioactive) nuclides in italics. Note that ...
7 elements have 6 stable isotopes apiece; 11 elements have 5 stable isotopes apiece; 9 elements have 4 stable isotopes apiece; 5 elements have 3 stable isotopes apiece; 16 elements have 2 stable isotopes apiece; 26 elements have 1 single stable isotope. These last 26 are thus called monoisotopic elements. [3] The mean number of stable isotopes ...
This list of nuclides shows observed nuclides that either are stable or, if radioactive, have half-lives longer than one hour. This represents isotopes of the first 105 elements, except for elements 87 ( francium ), 102 ( nobelium ) and 104 ( rutherfordium ).
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.
There are 26 such elements, as listed. Stability is experimentally defined for chemical elements, as there are a number of stable nuclides with atomic numbers over ~ 40 which are theoretically unstable, but apparently have half-lives so long that they have not been observed either directly or indirectly (from measurement of products) to decay.
"The first part of the list contain 80 of the first 82 elements in the periodic table" This statement implies that within the first 82 elements, there are two that are unstable. However, it isn't explained to the reader until the diagram that these are technetium and promethium. This information should all be available in one place.
The table of elements with stable isotopes looks very nice, I think. Good work – hope the level of this fits with the rest. Please note that I have not studied the whole article in detail, and I have not considered the FL criteria. By the way, remember units (i.e. years) of the half-lives mentioned in footnotes.
The heaviest stable element, lead (Pb), has many more neutrons than protons. The stable nuclide 206 Pb has Z = 82 and N = 124, for example. For this reason, the valley of stability does not follow the line Z = N for A larger than 40 ( Z = 20 is the element calcium ). [ 3 ]