Final answer:
Calcium crystallizes in a face-centered cubic structure, having one atom contributed by the corners and three atoms by the faces of the unit cell, totaling 4 calcium atoms in each unit cell. The correct answer is C.
Step-by-step explanation:
The number of calcium atoms in a unit cell of calcium can be determined by examining the crystal structure of calcium. Calcium crystallizes in a face-centered cubic (fcc) structure. In an fcc unit cell, each corner atom is shared by eight adjacent unit cells and each face atom is shared by two unit cells.
To find the total number of calcium atoms in a single unit cell, we calculate the contribution of the corner atoms and the face atoms. There are eight corner atoms, each contributing an eighth of an atom, resulting in one full atom (8 × 1/8 = 1 atom). Additionally, there are six face atoms, each contributing half an atom, amounting to three full atoms (6 × 1/2 = 3 atoms). Therefore, combining the contribution from corners and faces, we get a total of four atoms in the unit cell (1 + 3 = 4 atoms).
The correct answer is 4 calcium atoms in the unit cell of calcium, which corresponds to option (C).