Quarks are elementary particles and the fundamental building blocks of hadrons, such as protons and neutrons. Quarks are not typically referred to in terms of atomic or mass numbers, as those concepts are more applicable to atoms.
In the context of atoms, the atomic number represents the number of protons in the nucleus of an atom, while the mass number represents the sum of protons and neutrons. Since quarks are subatomic particles that make up protons and neutrons, they are not assigned individual atomic or mass numbers.
Each proton is composed of two up quarks (charge +2/3) and one down quark (charge -1/3). The neutron consists of one up quark and two down quarks. Therefore, it is the combination and arrangement of quarks within the nucleus that determine the atomic and mass numbers of atoms.
In summary, quarks themselves are not assigned atomic or mass numbers, but they play a crucial role in determining the properties of protons, neutrons, and the atoms they form.