Which of the following best describes a molecular formula?

• A. It indicates the arrangement of atoms within a molecule.
• B. It shows the exact number of each type of atom in a single molecule of a compound.
• C. It provides information about the physical properties of a compound.
• D. It represents the simplest whole-number ratio of atoms in a compound.

Answer: (B)

Verified step by step guidance

1. Understand that a molecular formula provides specific information about a compound's composition.
2. Recall that the molecular formula shows the exact number of each type of atom present in one molecule of the compound.
3. Differentiate the molecular formula from other types of formulas, such as the empirical formula, which shows the simplest whole-number ratio of atoms.
4. Recognize that the molecular formula does not indicate the arrangement of atoms (which is given by structural formulas) nor does it provide physical property information.
5. Conclude that the best description of a molecular formula is that it shows the exact number of each type of atom in a single molecule of a compound.