* Coefficient: The "2" in front of the formula means there are two molecules of C2H6.

* Subscripts: The subscripts "2" and "6" tell us the number of each type of atom within a single molecule.

Therefore:

* Carbon (C): 2 atoms per molecule * 2 molecules = 4 carbon atoms

* Hydrogen (H): 6 atoms per molecule * 2 molecules = 12 hydrogen atoms