What is defined as the simplest whole-number ratio of atoms of each element in a compound?

The empirical formula is defined as the simplest whole-number ratio of atoms of each element in a compound. This means it provides the most reduced form of the composition of a compound, indicating the proportion of each type of atom present, without specifying the actual number of atoms in a molecule or the arrangement of atoms.

For example, the empirical formula for glucose, which has the molecular formula C6H12O6, is CH2O. This reduction to the simplest whole-number ratio reflects the basic stoichiometry of the molecule.

In contrast, a molecular formula specifies the actual number of atoms of each element in a single molecule of a compound, which can be a multiple of the empirical formula. A structural formula represents how atoms are arranged in the compound and includes information on bond connectivity, while a systematic formula is not a standard term in chemistry for representing the composition of molecules.