If the radius of an atom is r, what is the length of the side of the face-centered cubic unit cell? A) 8^½r B) 2.25r C) 2r D) 4r/3^½ E) r

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Quizplus · Accepted Answer

In a face-centered cubic (FCC) unit cell, the atoms touch along the face diagonal. The face diagonal is equal to 4r (since it passes through the centers of two corner atoms and one face-centered atom). The face diagonal is also equal to √2 times the side length of the cube. Therefore, the side length of the cube is 4r/√2, which simplifies to 4r/3^½.

If the Radius of an Atom Is R, What Is