According to the Standard Model, nucleons consist of three up/down quarks confined by strong-force interactions as mediated by gluons. The net effect of these interactions is a nucleon model that has an equilateral-triangular form with a strong-force bond between each quark pair.However, this model assumes that strong-force interactions are equally likely between two same-charge quarks (which would otherwise be expected to repel each other) as they are between opposite-charge quarks.Should strong-force interactions only take place between opposite-charge quarks, then the nucleon model changes from an equilateral-triangular to a quark-chain model that involves only two strong-force bonds, each connecting the central quark to an oppositely charged quark. The quark-chain nucleon model leads to some interesting possibilities related to the structure of atomic nuclei, to electron orbitals and related covalent bonding patterns, and to the cause of radioactive decay in unstable elements.