Nuclei are composed of neutrons and protons (nucleons) but from another perspective they are composed of up and down quarks. Their binding energies are however largely determined by the number of alpha modules they contain. An alpha modules is a sequence of neutrons and protons linked together by spin pair bonding. An alpha module takes the form of -n-p-p-n-, or equjivalently, -p-n-n-p-. In addition to alpha modules nuclei contain isolated neutron-neutron spin pairs, isolated proton-proton spin pairs and isolated neutron-proton spin pairs. Furthermore there may a singleton neutron or a singleton proton in a nucleus.

Given below is a table showing the numbers of the various types of combinations. In the table the symbols j and k represent the integers that are greater than or equal to unity. The symbols α, nn, pp, np, n and p represent, respectively, an alpha module, a neutron spin pair, a proton spin pair, a neutron-proton spin pair, a singleton neutron and a singleton proton.