Total energy of the electron in hydrogen atom above 0 eV leads to continuation of energy states. large number of discrete ionized states. Paschen series. Palmar series.

Total energy of electron is negative implies that it is bound to the nucleus. As long as it is bound to the nucleus, its energy levels are quantised, i.e., it can only take definite values. But once the total energy of electron becomes zero, it means that the electron is now not bound to the nucleus any more. It is free from the attraction of nucleus. So, its energy can take continuous values. Thus, zero total energy of electron leads to continuous energy states.