Here are some non-examples of chemical symbols:

* Words: "water", "oxygen", "salt"

* Abbreviations: "H2O", "NaCl" (these are chemical formulas, not symbols)

* Numbers: 1, 2, 3

* Letters: a, b, c (unless they are part of a recognized chemical symbol)

Important Note: A chemical symbol is a one or two letter representation of an element. Here are some examples:

* H: Hydrogen

* O: Oxygen

* Fe: Iron

* Au: Gold

Let me know if you'd like more examples!