What does an empirical formula indicate?

An empirical formula represents the simplest whole-number ratio of the different types of atoms present in a compound. For example, the empirical formula for hydrogen peroxide, which has the molecular formula H₂O₂, is simply HO, indicating that there is a 1:1 ratio of hydrogen to oxygen in the compound. This means the empirical formula provides a straightforward way to understand the proportions of elements in a substance, without detailing the actual number of atoms or their arrangement in a molecule.

The other options focus on aspects such as total atom counts, specific arrangements of atoms, or molecular weights, which are not described by the empirical formula. The empirical formula simplifies the information into a ratio, making it a useful tool for analyzing the composition of compounds.