What is lowest ratio of atoms in molecule?

The lowest ratio of atoms in a molecule occurs in simple molecules like diatomic gases, such as hydrogen (H₂) or oxygen (O₂), where each molecule consists of just two atoms of the same element. In terms of different elements, the simplest molecule is water (H₂O), which has a ratio of 2 hydrogen atoms to 1 oxygen atom. Therefore, the lowest ratio generally reflects the simplest molecular structures with minimal atomic composition.