Which formula type represents how atoms are connected in a molecule?

• A. Molar mass formula
• B. Empirical formula
• C. Formula unit
• D. Structural formula

Answer: (D)

The main idea is how a chemical representation shows how atoms are connected in a molecule. A structural formula depicts the actual bonding pattern, showing which atoms are connected and how they share electrons. This reveals the arrangement of atoms and the bonds between them, such as H-O-H in water or the carbon–carbon and carbon–hydrogen connections in methane. In contrast, the empirical formula gives only the simplest whole-number ratio of elements, not how they are bonded. The term formula unit applies to ionic compounds and represents the simplest ratio of ions in a lattice, not the connectivity within a discrete molecule. The molar mass describes a property—the mass per mole derived from atomic masses—not how atoms are connected. So the representation that best shows how atoms are connected in a molecule is the structural formula.