---
title: "A student subjects a crystal of sodium chloride, \\(\\text{NaCl(s)}\\), to a mechanical shearing force, causing the crystal to cleave cleanly along a plane as represented in the diagram below. Which of the following claims best explains why ionic solids such as \\(\\text{NaCl(s)}\\) are brittle and fracture when a stress is applied?"
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url: "https://nerd-notes.com/ubq/119226/"
date_modified: "2026-08-19T12:39:27+00:00"
---

# A student subjects a crystal of sodium chloride, \(\text{NaCl(s)}\), to a mechanical shearing force, causing the crystal to cleave cleanly along a plane as represented in the diagram below. Which of the following claims best explains why ionic solids such as \(\text{NaCl(s)}\) are brittle and fracture when a stress is applied?

A student subjects a crystal of sodium chloride, \(\text{NaCl(s)}\), to a mechanical shearing force, causing the crystal to cleave cleanly along a plane as represented in the diagram below. Which of the following claims best explains why ionic solids such as \(\text{NaCl(s)}\) are brittle and fracture when a stress is applied?

![A diagram with a legend and two panels showing a two-dimensional slice of an ionic crystal lattice. The legend defines a white circle with a plus sign as a cation and a dark gray circle with a minus sign as an anion. The left panel, labeled Before Stress, shows a 3-by-3 grid of alternating cations and anions where every cation is adjacent only to anions horizontally and vertically. The right panel, labeled After Stress, shows the top row shifted horizontally by one particle position relative to the lower two rows. In this shifted alignment, cations in the top row lie directly above cations in the middle row, and anions in the top row lie directly above anions in the middle row. Vertical arrows between the top and middle rows indicate strong repulsions between adjacent like charges. No other text or annotations appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1787143167-QyE81m.jpg)

- **A.** The crystal fractures because the applied force shifts layers of ions, aligning ions of like charge adjacent to one another and producing strong electrostatic repulsions.
- **B.** The crystal fractures because the applied force disrupts a sea of delocalized valence electrons, preventing them from cushioning the movement of cations.
- **C.** The crystal fractures because directional covalent bonds between the sodium and chlorine atoms are rigid and cannot bend under mechanical pressure.
- **D.** The crystal fractures because the applied force pushes oppositely charged ions closer together, increasing attractive forces until the lattice collapses.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/119226/*