# From isospin of nucleons to hadrons

To my understanding, isospin was introduced for nucleons (neutrons and protons) because of their similar properties. When it was found out that they are made up of quarks, naturally the quarks could also be assigned isospin.

Is it then from the quark isospins that we can assign isospin to all hadrons?

Would it be more correct to say that isospin comes from quarks rather than nucleons (for which it was inteoduced)?

• you can say the same for baryon number too, and charge – anna v May 19 '17 at 17:19