Every element in the periodic table is represented by a unique chemical symbol, ... The symbols H for hydrogen and O for oxygen are used to represent H₂O.

If the chemical symbol consists of more than one letter, any subsequent letters are lowercase. Example: Hydrogen → H, Helium → He; 118 Elements and Their Symbols and Atomic Numbers.

The chemical symbol for oxygen is O. Makes sense. Calcium gets repped by a Ca. Sounds good. Hydrogen? H. Cobalt? Co. Lithium? Li. With you so far. Lead? Pb. There are actually a few things that ...

Element Symbols: Each element is represented by a unique one- or two-letter symbol, usually derived from its English or Latin name (e.g., H for Hydrogen, Au for Gold from "Aurum").

Chemical reactions can be summarised using symbol equations. Learn more in this KS3 Chemistry guide from Bitesize.