In physics, fundamental particles are typically treated as point particles. In this approximation, they have no size or shape whatsoever. They sort of have a location, but we can never exactly pinpoint this location in space, because quantum mechanics tells us that a particle never has an exact location.
The classical model of the electron does yield a non-zero radius, but this model is completely inaccurate when describing the size of the electron. It should not be used in any dimension-related context.
Protons and neutrons (and hadrons) are composite particles, though still subatomic. They do not have a point mass because they are made up of quarks and gluons.