Find the distance between the body-centred atom and one corner atom in sodium, a = 0.424 nm.

Explanation

To find the distance between the body-centered atom and one corner atom in sodium, we can follow these steps:

### Step 1: Understand the structure
In a body-centered cubic (BCC) lattice, there is one atom at each of the eight corners of the cube and one atom at the center of the cube. The edge length of the cube is given as \( a = 0.424 \, \text{nm} \).

### Step 2: Identify the position of the atoms
- The body-centered atom is located at the center of the cube, which can be represented as the coordinates \( (0.5a, 0.5a, 0.5a) \).
- The corner atom can be represented by the coordinates \( (0, 0, 0) \).
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