Isobar (nuclear)
A nuclear isobar are two nuclear species where the total number of protons and neutrons is the same for each nucleus, but the number of protons and neutrons making up that total are different. An isobar is similar to an isotope or isotone in that it describes a different atomic nucleus with similarities.[1] An isobar is a nuclide with the same total number of protons and neutrons, but a different number of each. This is as opposed to a nuclear isomer, which has the same number of protons, and the same number of neutrons, but is in a different energy state. Isobars always have the same mass number (which is the number written to the upper left of the chemical symbol).
Some examples of isobars include:
and
and
A daughter nucleus after beta decay will always be an isobar of the parent nucleus, since it doesn't change the number of nucleons in the nucleus the way alpha decay does. Note that different isobars must always have a different number of protons (different atomic number), and must therefore be different chemical elements.
PhET on building nuclides
The University of Colorado has graciously allowed us to use the following PhET simulation. This simulation explores how adding different numbers of protons and neutrons makes different nuclides, such as different isobars:
References
- ↑ A.D. McNaught and A. Wilkinson (Ed.). (2014, Dec. 12). IUPAC Compendium of Chemical Terminology (2nd ed., the "Gold Book") [Online]. Available: http://goldbook.iupac.org/I03263.html