* CaCO3 is an ionic compound with strong electrostatic attractions between the calcium (Ca2+) and carbonate (CO32-) ions. This strong attraction results in a rigid, crystalline structure that is solid at room temperature.
Let's look at the other options:
* NO (Nitrogen monoxide) is a gas at room temperature. It is a small molecule with weak intermolecular forces.
* BrCl (Bromine chloride) is a liquid at room temperature. It is a covalent compound with moderate intermolecular forces.
* SO2 (Sulfur dioxide) is a gas at room temperature. It is a polar molecule with weak intermolecular forces.
In general, ionic compounds tend to have higher melting points and are more likely to be solids at room temperature compared to covalent compounds.
