By using the SQCE (superposition of quantum confinement) model to calculate the thickness of shell for CdSe/CdS core/shell nanoparticles, the value obtained is 1.18 Angstrom (0.118 nm). Is this thickness value is acceptable because the diameter of an atom ranges from about 0.1 to 0.5 nanometers (1 × 10−10 m to 5 × 10−10 m). ???