Q.____________ is credited with the discovery of the neutron.

A nucleus $^{A}_{Z}X$ is made of $Z$ protons and $N=A-Z$ neutrons, together called nucleons; mass number $A$ = total nucleons, atomic number $Z$ = proton count (fixing the element). Scattering experiments show nuclear radius grows as $R=R_0A^{1/3}$, $R_0\approx1.2\ \text{fm}$, so nuclear volume $\propto A$: every nucleon occupies roughly the same volume, packed together almost like drops of an incompressible nuclear liquid. Because both mass and volume sca …