The chemical formula is C6H12O6 .
This is one molecule of Glucose ... the simple sugar that plants and algae make with photosynthesis, and the 'blood sugar' in human beings like you and me.
The formula tells us that each molecule is made of 6 Carbon atoms, 12 Hydrogen atoms, and 6 Oxygen atoms.
3 different elements (different kinds of atoms)
24 total atoms ... in every molecule