Step 1: Understanding the Concept:
In a crystal lattice, atoms are shared between adjacent unit cells. To find the total number of atoms effectively belonging to one unit cell, we must account for this sharing. Step 2: Detailed Explanation:
1. Corner Atoms: A BCC unit cell has 8 atoms at the corners. Each corner atom is shared by 8 adjacent unit cells.
- Contribution = $8 \times \frac{1}{8} = 1$ atom.
2. Body Center Atom: There is 1 atom at the very center of the cube. This atom is not shared with any other unit cell.
- Contribution = 1 atom.
3. Total Atoms: $1 \text{ (from corners)} + 1 \text{ (from center)} = 2$ atoms. Step 3: Final Answer
A Body-Centered Cubic (BCC) structure has 2 atoms per unit cell.