Chemistry - Solid State Question with Solution | TestHub

Question Explanation: Select the correct statements.

Concept: NaCl ionic crystal.

Solution:

1. The nearest neighbors of a Na⁺ ion are six Cl⁻ ions. This is a correct statement. In an NaCl crystal, each sodium ion (Na⁺) is octahedrally coordinated by six chloride ions (Cl⁻) at an equal distance.

2. A Na⁺ ion makes an octahedral void and is at the cube center. This statement is a bit muddled. The Cl⁻ ions form a cubic close-packed (CCP) arrangement, creating octahedral voids. The Na⁺ ions then occupy these octahedral voids, including the one at the center of the unit cell.

3. The Cl⁻ ions pack in a cubic close-packed arrangement. This is a correct statement. The chloride ions (Cl⁻) in the NaCl structure form a face-centered cubic (FCC) lattice, which is also known as a cubic close-packed (CCP) arrangement.

4. There are eight next nearest neighbors of a Na⁺ ion. This statement is incorrect. The next nearest neighbors of a Na⁺ ion are other Na⁺ ions located at the body diagonal positions relative to the central ion. There are twelve next-nearest neighbors for each Na⁺ ion, positioned along the axes.

Final answer: The correct options are (A), (B), (C).