Question
The only electron in the hydrogen atom resides under ordinary conditions on the first orbit. When energy is supplied, the electron moves to higher energy orbit depending on the amount of energy absorbed. When this electron returns to any of the lower orbits, it emits energy. Lyman series is formed when the electron returns the lowest orbit while Balmer series is formed when the electron returns to the second orbit. Similarly, Paschen, Brackett, and Pfind series are formed when electron returns to the third, fourth, and fifth from higher orbits, respectively.
Maximum number of lines produced when an electron jumps from nth level to ground level is equal to n(n−1)2.
If the electron comes back from the energy level having energy E2 to the energy level having energy E1, then difference may be expressed in terms of energy of photon as
E2 - E1 = ΔE, λ = hc/ΔE
Since h and c are constant, ΔE corresponds to definite energy, thus, each transition from one energy level to another will produce a light of definite wavelength. This is actually observed as a line in the spectrum of hydrogen atom.
Wave number of line is given by the formula
v = RZ2(1n21−1n22)
where R is a Rydberg constant.The wave number of electromagnetic radiation emitted during the transition of electron in between the two levels of Li2+ ion whose principal quantum numbers sum is 4 and difference is 2 is :