Final answer:
A unit cell of indium, which crystallizes in a face-centered cubic structure, contains 4 indium atoms. This is concluded by accounting for the atoms on the corners and faces of the cube that compose the unit cell.
Step-by-step explanation:
The question asks about the number of atoms in a unit cell of indium. Indium has a face-centered cubic (fcc) unit cell structure. In an fcc unit cell, there are four full atoms per unit cell. This can be calculated by considering that each of the eight corners of a cube has a ⅛ (¼) of an atom that contributes to the unit cell, adding up to 1 atom, and each of the six face-centered atoms contributes ½, adding up to 3 atoms.
Combined, this equals 4 atoms per unit cell for indium. Furthermore, we can refer to the factor-label method for calculations involving the number of atoms based on unit cells or sample masses as illustrated in the given problem sets.