Question

Nuclei with even A obey​

Answer 1

Answer:

In nuclear physics, properties of a nucleus depend on evenness or oddness of its atomic number Z, neutron number N and, consequently, of their sum, the mass number A. Most importantly, oddness of both Z and N tends to lower the nuclear binding energy, making odd nuclei generally less stable. This effect is not only experimentally observed, but is included in the semi-empirical mass formula and explained by some other nuclear models, such as the nuclear shell model. This difference of nuclear binding energy between neighbouring nuclei, especially of odd-A isobars, has important consequences for beta decay.

Also, the nuclear spin is integer (mostly 0) for all even-A nuclei and non-integer (half-integer) for all odd-A nuclei.

Even vs. odd mass number (A).

Even Odd Total

Stable 151 101 252

Long-lived 25 9 34

All primordial 176 110 286