---
title: "A student investigates the physical properties of four unknown crystalline solids, \\(W\\), \\(X\\), \\(Y\\), and \\(Z\\). The results of the student’s tests are summarized in the table below.  | Solid | Melting point (\\(^\\circ\\text{C}\\)) | Electrical conductivity (solid state) | Electrical conductivity (liquid state) | | :— | :— | :— | :— | | \\(W\\) | \\(119\\) | Nonconductor | Nonconductor | | \\(X\\) | \\(801\\) | Nonconductor | Good conductor | | \\(Y\\) | \\(1085\\) | Good conductor | Good conductor | | \\(Z\\) | \\(1710\\) | Nonconductor | Nonconductor |  Based on the data in the table, which of the following statements correctly identifies one of the solids and provides the appropriate structural justification?"
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url: "https://nerd-notes.com/ubq/121465/"
date_modified: "2026-08-23T05:04:42+00:00"
---

# A student investigates the physical properties of four unknown crystalline solids, \(W\), \(X\), \(Y\), and \(Z\). The results of the student’s tests are summarized in the table below.

| Solid | Melting point (\(^\circ\text{C}\)) | Electrical conductivity (solid state) | Electrical conductivity (liquid state) |
| :— | :— | :— | :— |
| \(W\) | \(119\) | Nonconductor | Nonconductor |
| \(X\) | \(801\) | Nonconductor | Good conductor |
| \(Y\) | \(1085\) | Good conductor | Good conductor |
| \(Z\) | \(1710\) | Nonconductor | Nonconductor |

Based on the data in the table, which of the following statements correctly identifies one of the solids and provides the appropriate structural justification?

A student investigates the physical properties of four unknown crystalline solids, \(W\), \(X\), \(Y\), and \(Z\). The results of the student's tests are summarized in the table below.

| Solid | Melting point (\(^\circ\text{C}\)) | Electrical conductivity (solid state) | Electrical conductivity (liquid state) |
| :--- | :--- | :--- | :--- |
| \(W\) | \(119\) | Nonconductor | Nonconductor |
| \(X\) | \(801\) | Nonconductor | Good conductor |
| \(Y\) | \(1085\) | Good conductor | Good conductor |
| \(Z\) | \(1710\) | Nonconductor | Nonconductor |

Based on the data in the table, which of the following statements correctly identifies one of the solids and provides the appropriate structural justification?

- **A.** Solid \(W\) is a network covalent solid because breaking the weak covalent bonds between its atoms requires minimal thermal energy.
- **B.** Solid \(X\) is a metallic solid because the presence of mobile valence electrons in the liquid state allows it to conduct electricity.
- **C.** Solid \(Y\) is an ionic solid because its high melting point is a result of strong electrostatic attractions between cations and anions that conduct electricity in the solid state.
- **D.** Solid \(Z\) is a network covalent solid because melting it requires breaking strong covalent bonds throughout an extended three-dimensional lattice, and its valence electrons remain localized in fixed bonds.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/121465/*