How many chloride ions are present arounda sodium ion in the sodium chloride crystal ?

To determine the number of chloride ions present around a sodium ion in the sodium chloride crystal, we need to consider the crystal structure of sodium chloride.

Sodium chloride has a face-centered cubic (FCC) crystal structure, which means that each sodium ion is surrounded by six chloride ions, and each chloride ion is surrounded by six sodium ions.

In the FCC structure, the sodium ions are located at the corners of the unit cell, while the chloride ions are located at the center of each face of the unit cell.

Since each sodium ion is surrounded by six chloride ions, we can conclude that there are six chloride ions present around a sodium ion in the sodium chloride crystal.