When an electron in a hydrogen atom is in the n = 3 state, is it on average farther from the nucleus than in the ground state.
The hydrogen atom has one electron, therefore, the ground state of the hydrogen is at n=1 which is closest to the nucleus. When the hydrogen atom gains sufficient amount of energy, it is excited to higher energy levels (n=2 and n=3) which are relatively far from the nucleus when compared to the ground state. When the excited hydrogen atom loses energy, it returns back to the ground state.