In a body-centred and face-centred arrangement of atoms of an element, what will be the number of atoms present in respective unit cells ?

Explanation

To determine the number of atoms present in a body-centered cubic (BCC) and face-centered cubic (FCC) unit cell, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Body-Centered Cubic (BCC) Structure**:
- In a BCC unit cell, there is one atom located at each of the eight corners of the cube and one atom at the center of the cube.
- Each corner atom contributes \( \frac{1}{8} \) of its volume to the unit cell because it is shared among eight adjacent unit cells.
- The center atom contributes fully, as it is entirely contained within the unit cell.
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