What information is most important in determining the size of an orbital?

The information that is the most essential in order to determine the size of the orbital would be the quantum number n or the principal quantum number. It is an indirect method or measure in describing the electron orbital's size.  It has value of an integer and it can never have a value of zero.

Africans learned what the europeans wanted them to learn. instead of learning about african history and current information that could and would them they learned solely what europe wanted them to. and not everyone received the same education, some received better and others none.