It's important to recognise which elements are written with a subscript 2 and which are not. Take care to use the correct form in chemical equations involving these elements.

You may need to multiply both sides if the number of an atom on the right is not a multiple of the atoms on the left. 5 Repeat steps 3 and 4 until the chemical equation is balanced.

With the discovery of quantum mechanics, Paul Dirac announced 1 that the underlying laws of chemistry were completely known, the only hitch being that the resulting equations were too difficult to ...