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Lead (82 Pb) has four observationally stable isotopes: 204 Pb, 206 Pb, 207 Pb, 208 Pb. Lead-204 is entirely a primordial nuclide and is not a radiogenic nuclide.The three isotopes lead-206, lead-207, and lead-208 represent the ends of three decay chains: the uranium series (or radium series), the actinium series, and the thorium series, respectively; a fourth decay chain, the neptunium series ...
There are three stable "daughter" Pb isotopes that result from the radioactive decay of uranium and thorium in nature; they are 206 Pb, 207 Pb, and 208 Pb. 204 Pb is the only non-radiogenic lead isotope, therefore is not one of the daughter isotopes.
The high number of isotopes is consistent with lead's atomic number being even. [g] Lead has a magic number of protons (82), for which the nuclear shell model accurately predicts an especially stable nucleus. [39] Lead-208 has 126 neutrons, another magic number, which may explain why lead-208 is extraordinarily stable. [39]
The darker more stable isotope region departs from the line of protons (Z) = neutrons (N), as the element number Z becomes larger. This is a list of chemical elements by the stability of their isotopes. Of the first 82 elements in the periodic table, 80 have isotopes considered to be stable. [1] Overall, there are 251 known stable isotopes in ...
Stable even–even nuclides number as many as three isobars for some mass numbers, and up to seven isotopes for some atomic numbers. Conversely, of the 251 known stable nuclides, only five have both an odd number of protons and odd number of neutrons: hydrogen-2 ( deuterium ), lithium-6 , boron-10 , nitrogen-14 , and tantalum-180m .
Specifically, 206 Pb is formed from 238 U, 207 Pb from 235 U, and 208 Pb from 232 Th. In rocks that contain uranium and thorium, the excess amounts of the three heavier lead isotopes allows the rocks to be "dated", thus providing a time estimate for when the rock solidified and the mineral held the ratio of isotopes fixed and in place.
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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] Neutron number increases along the line of beta stability at a faster rate than atomic number.