In the cubic closest-packed structure of sodium chloride, which ions are touching or nearly touching?
I.sodium ions and sodium ions
II.chloride ions and chloride ions
III.sodium ions and chloride ions
A)I only
B)II only
C)III only
D)II and III only
E)I and III only

Question

Quizplus · Accepted Answer

In the cubic closest-packed structure of sodium chloride, the sodium ions and chloride ions are arranged in a way that forms a face-centered cubic lattice. In this lattice, each ion is touching or nearly touching six ions of the opposite kind. Therefore, the sodium and chloride ions are in close proximity to each other, hence, touching or nearly touching. Therefore, option III is correct. On the other hand, since the sodium ions are arranged in a cubic closest-packed structure, they are also in close proximity to each other, hence, touching or nearly touching. Therefore, option I is correct. However, option II is not correct because chloride ions are not arranged in a cubic closest-packed structure.

In the Cubic Closest-Packed Structure of Sodium Chloride, Which Ions