Question

The sharp melting point of crystalline solids is due to _________.

• A. a regular arrangement of constituent particles observed over a short distance in the crystal lattice
• B. a regular arrangement of constituent particles observed over a long distance in the crystal lattice
• C. the same arrangement of constituent particles in a different direction
• D. different arrangement of constituent particles in different directions

Answer 1

The correct option is B

a regular arrangement of constituent particles observed over a long distance in the crystal lattice

Explanation:

Crystalline solid:

• “A crystalline solid usually consists of a large number of small crystals, each of them having a definite characteristic geometrical shape.”
• “In a crystal, the arrangement of constituent particles (atoms, molecules or ions) is ordered.”
• Examples of crystalline solids are Sodium chloride$\left(\mathrm{NaCl}\right)$ and quartz.
• Crystalline solids have sharp well-melting points because all the components of a crystalline solid are present at the same distance from each other.
• The atoms or molecules or ions in crystalline solids are arranged in regular arrangements that create local environments which are the same throughout a long distance in a crystal lattice.

Hence, the correct option is B. The sharp melting point of crystalline solids is due to a regular arrangement of constituent particles observed over a long distance in the crystal lattice.