Which is a difference between molecular compounds and ionic compounds?
Molecular compounds typically form between a metal and a nonmetal, while ionic compounds typically form between nonmetals.
Molecular compounds result from the transfer of electrons between atoms to form ions, while ionic compounds result from the sharing of electrons between neutral atoms.
Molecular compounds are formed of discrete, neutral molecules, while ionic compounds are formed of large repeating arrays of opposite charges.
Molecular compounds have high melting points and high boiling points, while ionic compounds are typicaly found as gases or low-melting solids and low-boiling liquids.
The Correct Answer and Explanation is :
The correct statement is: “Molecular compounds are formed of discrete, neutral molecules, while ionic compounds are formed of large repeating arrays of opposite charges.”
Explanation:
Molecular compounds and ionic compounds differ fundamentally in their bonding, structure, and properties:
- Bonding and Formation:
- Molecular Compounds: Formed when two or more nonmetal atoms share electrons through covalent bonds, resulting in discrete, neutral molecules. For example, water (H₂O) consists of H₂O molecules held together by covalent bonds.
- Ionic Compounds: Formed when metal atoms transfer electrons to nonmetal atoms, creating positively charged cations and negatively charged anions. These oppositely charged ions are held together by strong electrostatic forces in a repeating lattice structure. An example is sodium chloride (NaCl), where Na⁺ and Cl⁻ ions form a crystalline lattice.
- Structure:
- Molecular Compounds: Consist of distinct, separate molecules. These molecules interact through weaker intermolecular forces, such as hydrogen bonds or van der Waals forces.
- Ionic Compounds: Do not consist of discrete molecules but rather form extensive networks of ions in a lattice arrangement, leading to a continuous structure.
- Physical Properties:
- Molecular Compounds: Generally have lower melting and boiling points compared to ionic compounds. They can exist as gases, liquids, or low-melting solids at room temperature. They are poor conductors of electricity in all states.
- Ionic Compounds: Typically have high melting and boiling points due to the strong ionic bonds. They are usually solid at room temperature and conduct electricity when melted or dissolved in water, as the ions are free to move.
Understanding these distinctions is crucial in chemistry, as they influence the behavior and applications of various compounds.