Hydrogen atom: The electronic ground state of hydrogen atom contains one electron in the first orbit. If sufficient energy is provided, this electron can be promoted to higher energy levels. The electronic energy of a hydrogen-like species (any atom//ions with nuclear charge Z and one electron) can be given as `E_(n)=-(R_(H)Z^(2))/(n^(2))` where `R_(H)= "Rydberg constant," n= "principal quantum number"` The energy in Joule of an electron in the second orbit of H- atom is:
