Here's the breakdown:
* Na represents Sodium, with an atomic mass of approximately 23.
* Cl represents Chlorine, with an atomic mass of approximately 35.5.
Since Chlorine has a higher atomic mass, it contributes more to the overall mass of the NaCl molecule. However, the ratio of atoms in the formula is 1:1, meaning there's one sodium atom for every chlorine atom.
Therefore, both elements have an equal share of atoms in the formula.
