Sodium Chloride's Ionic Crystal Lattice Structure

Steps:

• Recall NaCl forms a face-centered cubic (FCC) lattice with Na⁺ and Cl⁻ ions alternating in a 1:1 ratio.
• Identify key features: each ion surrounded by six oppositely charged ions in octahedral coordination; no like ions adjacent.
• Examine diagrams for 3D arrangement showing alternating spheres or ions along edges and faces.
• Select the option matching this alternating pattern without distortions.

Why A is correct:

• Diagram A depicts the FCC lattice with alternating Na⁺ and Cl⁻ ions, adhering to the ionic bonding rule where oppositely charged ions maximize attraction and minimize repulsion.

Why the others are wrong:

• B shows adjacent like ions, violating the alternating charge requirement in ionic lattices.
• C represents a linear or 1D chain, not the 3D cubic structure of NaCl.
• D illustrates a close-packed metallic lattice, lacking distinct ion alternation.

Final answer: A