How is an isobar defined?

An isobar is defined as atoms that have the same atomic mass number but different atomic numbers. The atomic mass number represents the total number of protons and neutrons in an atom's nucleus, while the atomic number indicates the number of protons. Since isobars share the same mass number, they possess the same total number of nucleons, but the differing atomic numbers means that they are different elements.

This understanding is fundamental in nuclear chemistry and helps differentiate isobars from other classifications of isotopes, which may share the same atomic number but differ in mass number or have different neutron counts. The nuances of this classification are crucial in understanding nuclear reactions, decay processes, and stability in elements.