Chapter 10, Problem 10.94SP

Interpretation Introduction

Interpretation:

The length of $\text{Na-H}$ bond in picometers has to be calculated.

Concept Introduction:

Face-centered cubic:

In face-centered cubic unit cell, each of the six corners is occupied by every single atom.  Each face of the cube is occupied by one atom.

Each atom in the corner is shared by eight unit cells and each atom in the face is shared by two unit cells.  Thus the number of atoms per unit cell in FCC unit cell is,

$\text{8}\text{×}\frac{\text{1}}{\text{8}}\text{atoms}\text{in}\text{corners}\text{+}\text{6}\text{×}\frac{\text{1}}{\text{2}}\text{atoms}\text{in}\text{faces}\text{=}\text{1}\text{+}\text{3}\text{=}\text{4}\text{atoms}$