What is a subscript in chemistry?

In chemistry, a subscript is a small number written at the bottom right of a chemical symbol to indicate the number of atoms of that element in a molecule or compound. For example, H2O indicates that there are two hydrogen atoms and one oxygen atom in a water molecule.

Subscripts are important in chemical formulas to communicate the precise composition of a substance. They help to distinguish between different compounds with the same elements but in different ratios. The subscripts also play a critical role in balancing chemical equations by ensuring that the total number of atoms of each element is the same on both sides of the equation.