A Level Chemistry OCR Practice Exam

What is represented by a displayed formula in a chemical compound?

1. The ratio of each atom in the substance

2. The three-dimensional shape of the molecule

3. The relative positioning of all atoms and bonds

4. The total number of atoms in the molecule

The correct answer is: The relative positioning of all atoms and bonds

A displayed formula is a two-dimensional depiction of a chemical compound that illustrates how atoms are arranged, their connectivity, and the types of bonds between them. This representation clearly indicates which atoms are bonded to each other and the connectivity between those atoms, reflecting the molecular structure. The displayed formula allows chemists to visualize the specific arrangement of atoms within the molecule, providing important insight into its chemical behavior and reactivity. It includes details like single, double, or triple bonds and shows how atoms are connected, which is crucial for understanding the properties and function of the compound in various chemical contexts. While the other options touch on aspects of chemical structure, they do not accurately describe what a displayed formula specifically conveys. For instance, while the ratio of atoms is important, it is not the primary focus of a displayed formula but rather more commonly represented by empirical formulas. Similarly, the three-dimensional shape of a molecule would be better represented by models like ball-and-stick or space-filling representations, and the total number of atoms is not indicated in the displayed formula, which emphasizes connectivity instead.