Step 1: Concept Overview:
This question assesses your understanding of the Simple Cubic (SC) crystal lattice. We need to verify each statement's accuracy.
Step 2: Detailed Analysis:
A. Atoms per unit cell: 1: In a Simple Cubic lattice, atoms are located at each of the 8 corners. Each corner atom contributes 1/8 to the unit cell. Thus, the total number of atoms per unit cell is \( 8 \times \frac{1}{8} = 1 \). This statement is correct.
B. Packing factor: 0.52: The Atomic Packing Factor (APF) represents the volume fraction occupied by atoms in the crystal structure. For SC, \( \text{APF} = \frac{\text{Volume of atoms}}{\text{Volume of unit cell}} = \frac{1 \times \frac{4}{3}\pi r^3}{a^3} \). Since \( a = 2r \) in SC, \( \text{APF} = \frac{\frac{4}{3}\pi r^3}{(2r)^3} = \frac{\frac{4}{3}\pi r^3}{8r^3} = \frac{\pi}{6} \approx 0.5236 \). This statement is correct.
C. Iron as an SC example: This statement is incorrect. Iron (Fe) exhibits a Body-Centered Cubic (BCC) structure at room temperature (alpha-iron) and a Face-Centered Cubic (FCC) structure at higher temperatures (gamma-iron). Polonium (Po) is the only element known to have a simple cubic structure under standard conditions.
D. Coordination Number: 6: The coordination number indicates the number of nearest neighbors. In SC, each atom has 6 nearest neighbors: one along each positive and negative direction of the x, y, and z axes. This statement is correct.
Step 3: Conclusion:
Statements A, B, and D are correct; statement C is incorrect. Therefore, the correct answer includes only A, B, and D.