Question

Which of the following statements explains why silicon dioxide has a high melting point?

A chemistry lab investigates the physical properties (melting point, solubility in water, and electrical conductivity) of three substances: sodium chloride (NaCl), glucose (C₆H₁₂O₆), and magnesium oxide (MgO). They observe that: - NaCl and MgO conduct electricity in molten form but not as solids. - Glucose does not conduct electricity in any form. - NaCl and MgO have high melting points, while glucose melts at a lower temperature. They conclude that NaCl and MgO are ionic compounds, while glucose is covalent.