1. The elements present in a compound: The symbols in the formula represent the elements that make up the compound. For example, H₂O tells you that water is made of hydrogen (H) and oxygen (O).

2. The ratio of atoms of each element: The subscripts in the formula indicate the number of atoms of each element in a molecule of the compound. For example, H₂O tells you that there are two hydrogen atoms for every one oxygen atom in a water molecule.

3. The empirical formula: This is the simplest whole number ratio of atoms in a compound. For example, glucose has the molecular formula C₆H₁₂O₆, but its empirical formula is CH₂O, indicating a 1:2:1 ratio of carbon, hydrogen, and oxygen atoms.

Let me know if you'd like more details on any of these points!