Statement I: The positively charged nucleus of an atom has a radius of almost ${10}^{-15}$ m.
Statement II : In $\mathrm{\alpha }$-particle scattering experiment, the distance of closest approach for $\mathrm{\alpha }$-particles is $\approx {10}^{-15}$m.

In $\mathrm{\alpha }$-particle scattering experiment, Rutherford found a small number of $\mathrm{\alpha }$-particles which were scattered. back through an angle approaching to ${180}^0$. This is possible only if the positive charges are concentrated at the centre or nucleus of the atom.