The choice of symbols for chemical elements is based on historical reasons, practicality, and convention. The symbol "O" for oxygen (atomic number 8) is derived from the first letter of its English name. The use of symbols instead of spelling out the full name of an element allows for easier representation and concise notation in chemical formulas and equations.
Using the symbol "O" for oxygen helps avoid confusion with the number zero (0) when communicating chemical information. Since zero is a numerical value, using "O" as the symbol for oxygen reduces the likelihood of misinterpretation or ambiguity in scientific notations.
Overall, the adoption of symbols for chemical elements, including "O" for oxygen, is a standardized convention that has been established over time to facilitate efficient communication in the field of chemistry.