This paper purposes an explanation for the recent evidence for the violation of lepton universality in beauty-quark decays at CERN’s Large Hadron Collider. A beauty meson (B+) transforms into a strange meson (K+) with the emission of either electron-positron (e+e−) or muon-antimuon (µ+µ−). The ratio (RK) of branching fractions for B+ → K+µ+µ− and B+→ K+e+e− decays is measured to be RK = 0.846 instead of 1 in the violation of lepton universality in the Standard Model. This paper proposes that the violation is derived from the binary isotope mixture of two beauty-quarks, b7 (4,979 MeV mass) and b8 (143,258 MeV mass) whose masses are calculated from the periodic table of elementary particles. b7 is the observable B, while b8 is the hidden B to preserve the generation number symmetry between the three lepton family generations and the three quark family generations in the Standard Model. The preservation of the generation number symmetry forbids b8 to decay into K+µ+µ−. In the transition state involving the virtual particles (γ, W± and Z°) before the decay, b7 and b8 emerge to form the binary isotope mixture from B. The rates of emergence as the rates of diffuse in Graham's law of diffusion are proportional to inverse square root of mass. The rate ratio between b8 /b7 is (4,979 /143,258) 1/2 = 0.1864. Since b7 decays into K+, e+e−, and µ+µ−, while b8 decays into K+ , e+e− , and forbidden µ+µ−, the calculated ratio (RK) of branching fractions for B+ → K+µ+µ− and B+→ K+e+e− is 0.5/(0.1864 x 0.5+ 0.5) = 0.843 in excellent agreement with the observed 0.846. The agreement between the calculated RK and the observed RK confirms the validity of the periodic table of elementary particles which provides the answers for the dominance of matter over antimatter, dark-matter, and the mass hierarchy of elementary particles.