Isobar (nuclear)
A nuclear isobar are when two nuclear species exhibit the same total number of nucleons for each nucleus, but the number of protons and neutrons making up that total are different. In contrast, a nuclear isomer would be two nuclear species that have the same number of protons and neutrons, but the elements vary in energy state. An isobar is similar to an isotope or isotone in that it describes a different atomic nucleus with similarities.[1] 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
In the above examples, and are isobars since they both have 40 nucleons in their nuclei. The same is true for and , which each have 14 nucleons. 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:
For Further Reading
- Isotope
- Isotone
- Nuclide
- Nuclear isomer
- Strong force
- Or explore a random page
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