List the properties of ionic and covalent compounds.
The Correct Answer and Explanation is:
Properties of Ionic and Covalent Compounds
Answer:
- Ionic Compounds:
- High melting and boiling points
- Typically solid at room temperature
- Conduct electricity when molten or dissolved in water
- Often soluble in water but insoluble in nonpolar solvents
- Hard and brittle
- Covalent Compounds:
- Low to moderate melting and boiling points
- Can be solid, liquid, or gas at room temperature
- Do not conduct electricity
- Often soluble in nonpolar solvents but insoluble in water
- Typically softer and more flexible if solid
Explanation:
Ionic and covalent compounds exhibit distinct properties due to their different types of bonding. Ionic compounds are formed when atoms transfer electrons, typically between metals and nonmetals, resulting in positively charged cations and negatively charged anions. These opposite charges attract, forming a strong electrostatic force, or ionic bond, which holds the ions together in a crystal lattice structure. This lattice is responsible for the high melting and boiling points of ionic compounds, as considerable energy is required to break these bonds. Ionic compounds are also brittle because the rigid structure shatters if the ions are displaced. Furthermore, ionic compounds conduct electricity when dissolved in water or melted, as the ions become free to move and carry charge. In solid form, however, they do not conduct electricity because the ions are fixed within the lattice.
In contrast, covalent compounds form when nonmetal atoms share electrons, creating covalent bonds. These compounds often have lower melting and boiling points since covalent bonds, though strong within a molecule, are weaker between molecules (intermolecular forces), so less energy is needed to separate them. Covalent compounds are usually nonconductive because they do not produce ions in water or contain mobile charges. They can be gases, liquids, or solids at room temperature, depending on the strength of their intermolecular forces. Covalent compounds tend to dissolve in nonpolar solvents, aligning with the “like dissolves like” principle, as both covalent compounds and nonpolar solvents lack an ionic character. In general, the softness and flexibility of many covalent compounds stem from the relatively weaker attractions between individual molecules.