Ionic Compounds' Physical Properties

Steps:

• Recall that ionic compounds form from metal and non-metal ions with strong electrostatic attractions.
• Identify key properties: high melting/boiling points, solid state at room temperature, conductivity in solution or molten form.
• Evaluate each option against these properties.
• Select the option that universally applies to standard ionic compounds.

Why A is correct:

• Ionic bonds create rigid lattices with high lattice energy, making all typical ionic compounds solids at room temperature (e.g., NaCl melts at 801°C).

Why the others are wrong:

• B: Solid ionic compounds do not conduct electricity at room temperature due to fixed ions; conduction requires mobility in liquid or solution.
• C: Not all ionic compounds are soluble in water; solubility depends on lattice energy vs. hydration energy (e.g., AgCl is insoluble).
• D: Ionic compounds have intramolecular ionic bonds, not intermolecular forces, which apply to molecular compounds.

Final answer: A