The mass of a face-centered cubic unit cell is
A) Two times the mass of one atom.
B) Five times the mass of one atom.
C) Equal to the mass of one atom.
D) Six times the mass of one atom.
E) Four times the mass of one atom.

Question

Quizplus · Accepted Answer

In a face-centered cubic (FCC) unit cell, there are 8 corner atoms each contributing 1/8th of their mass to the unit cell and 6 face atoms each contributing 1/2 of their mass. Since there are 8 corners and 6 faces, the total contribution is (8*1/8) + (6*1/2) = 1 + 3 = 4 atoms. Therefore, the mass of an FCC unit cell is equivalent to the mass of four atoms.

The Mass of a Face-Centered Cubic Unit Cell Is