Neutron/Talk

I'm not sure the description of particles in a nucleus as resonances between protons and neutrons by exchange of pions is up to date. I remember it was one of the first strong interaction models that appear, but that was before quarks and QCD. Is that description still valid in a quark context?

Yep. QCD provides a little more detail to the picture, of course, but you still get triples of up-downs which correspond to proton-neutrons, and since these are colorless and gluons very sticky you tend to get quark-antiquark pairs connecting them, and these are pions.