Which of the following best describes intramolecular forces?

• A. Forces responsible for the attraction between ions in a crystal lattice.
• B. Forces that hold atoms together within a molecule, such as covalent or ionic bonds.
• C. Forces that cause phase changes, such as melting and boiling.
• D. Forces that occur between different molecules, such as hydrogen bonding.

Answer: (B)

Verified step by step guidance

1. Understand that intramolecular forces are the forces that hold atoms together within a single molecule. These include covalent bonds, ionic bonds, and metallic bonds.
2. Recognize that these forces are different from intermolecular forces, which occur between separate molecules and are responsible for phenomena like boiling and melting points.
3. Note that forces responsible for attraction between ions in a crystal lattice are ionic bonds, which are a type of intramolecular force when considering the ions within a compound.
4. Identify that forces causing phase changes, such as melting and boiling, are typically due to intermolecular forces, not intramolecular forces.
5. Conclude that the best description of intramolecular forces is 'Forces that hold atoms together within a molecule, such as covalent or ionic bonds.'