Chapter 10, Problem 10.92SP

Interpretation Introduction

Interpretation:

The number of Sodium ions that touch each of ${\text{H}}^{\text{-}}$ ion and the number of ${\text{H}}^{\text{-}}$ ions that each Sodium atoms has to be given.

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,

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