Which characteristic is given by the principal quantum number?

a. orbital size

b. orbital mass

c. orbital shape

d. orbital orientation

ah, I said why not the shape and orientation, but forgot to comment why not mass. b) is also semi-possible if you take it means the mass of the electron and not the orbit per say. Then yes because the mass of the electron is tied to its energy levels by the deBroglie relationship. However the question asks specifically why "orbital mass" and I don't know what that is so I think it's just a "distraction" answer