Formula
One Hydrogen molecule is expressed as H2. It means, there are two
Hydrogen atoms in that molecules.
Again, one molecule of water is expressed as H2O, meaning, it
contains two Hydrogen atoms and an Oxygen atom. The following table shows
formulas of some common molecules:
Name of Molecule & Formula
Nitrogen = N2
Ammonia = NH3
Chlorine = Cl2
Sulfuric Acid = H2SO4
Hydrochloric Acid = HCl