Let $F_{pp},F_{pn}$ and $F_{nn}$ denote  the magnitude of net force by a proton on a proton, by a proton on a neutron and by a neutron on a neutron respectively. Neglect gravitational force. When the separation is $1 \mathrm{fm}$ :

The neutral particle is the neutron. The net force between a neutron and a proton is therefore equivalent.
Two positively charged protons will repel one another when they come together. As a result, a proton's net force on another proton is less than its net force on a neutron.