Simple Cubic = 1 atom Body-centered = 2 atoms Face-centered = 4 atoms
Work Step by Step
Simple cubic cells have one-eighth of a sphere inside the realm of the cell on each vertex, adding up to one whole atom. Body-centered cubic cells have the fractions of spheres on each vertex also, but include one whole atom in the center, two atoms altogether. Face-centered cubic cells have simple cubic cell's vertex spheres, but also have one-half of a sphere flushed on each face, totaling 4 spheres.