In a chemical formula such as H2O, what do the small numbers (subscripts) in the formula represent?

• A. The charge of each atom in the molecule
• B. The number of atoms of each element in a molecule
• C. The mass number of each element
• D. The atomic number of each element

Answer: (B)

Verified step by step guidance

1. Understand that a chemical formula represents the types and numbers of atoms in a molecule.
2. Recognize that the small numbers (subscripts) written to the right and slightly below the element symbols indicate how many atoms of that element are present in one molecule of the compound.
3. Note that these subscripts are not related to the charge, mass number, or atomic number of the elements; instead, they specifically count the atoms.
4. For example, in H\2O, the subscript '2' after H means there are two hydrogen atoms, and since there is no subscript after O, it means there is one oxygen atom.
5. Therefore, the subscripts tell us the number of atoms of each element in a molecule, which is essential for understanding the molecule's composition.