In chemical formulas, what does the subscript indicate?

In chemical formulas, the subscript indicates the number of atoms of a specific element present in a molecule. For example, in the formula H₂O, the subscript "2" next to the hydrogen (H) signifies that there are two hydrogen atoms for every one oxygen atom in the water molecule. This is a fundamental aspect of understanding chemical composition, as it allows for clear representation of how many of each type of atom are involved in a compound.

The other options do not correctly define the role of subscripts. The first option refers to the variety of elements rather than the quantity of a specific element. The second option discusses the total number of atoms, which is represented by summing up all the atoms in the formula, not just through the subscript. Lastly, molecular weight is determined by the atomic weights of the constituent elements and their quantities but is not indicated by subscripts specifically.