Question

What qualitative and quantitative information is conveyed by a symbol?

Answer 1

There is not only one thing specifically represented by any symbol of any element, in both quality and quantity. The symbol is used differently for different purposes, such as in chemical reaction or in determining the quantity of protons or neutrons.

Complete answer:
The symbol of any element represents various things, mainly the symbol represents the name of the element. Suppose the element is $O$ , thus one can know that this element is oxygen. This is considered qualitative.
Many times the element is also represented as $^{8}O$ , here the 8 represents its atomic number. It states that oxygen is the eighth element on the periodic table. Moreover, it also states the number of protons, neutrons and electrons residing in it.
As the number of protons and electrons are the same, we can say that there are eight protons and electrons in an oxygen atom by looking at the number given in the symbol.
Sometimes, a symbol is also written as $_{16}^{8}O$ , here the number 16 represents its atomic weight. It might be round figured for the sake of simplicity. Thus, 8 and 16 represent atomic number and atomic weight respectively, and they are quantitative.
These two are the main qualitative and quantitative information given by any symbol. A symbol might give more information about itself.
Like, in a chemical reaction the symbol of an element represents that it is one atom. For example, if there is just $O$ written in a reaction, then there is only one oxygen atom taking part in the reaction. If there is ${{O}_{2}}$ written, then there are two oxygen atoms taking part in the reaction.
Thus, various types of information can be obtained by the symbolic representation of an element.

Note:
A symbol in a reaction can also represent its charge, for example if only $O$ is written, then there is no charge on the atom, but if there is ${{O}^{2-}}$ written, then there is two negative charge on the atom. Quantitative information is easy to recognize as you only have to remember what represents what, but qualitative information is hard to recognize as you have to remember the names and symbols of the elements.