The change in energy of a one-electron atom or ion for an electronic transition from the initial energy level n_i to the final energy level n_f is given by
$\Delta$ E = -(2.18*10^-¹⁸J)
Z² $\left( \frac { 1 } { n _ { f } ^ { 2 } } - \frac { 1 } { n _ { i } ^ { 2 } } \right.$
Which of the following species will have the longest wavelength emission line for the transition between the n_i = 2 and n_f = 1 levels?

Question

The change in energy of a one-electron atom or ion for an electronic transition from the initial energy level n_i to the final energy level n_f is given by

\Delta

E = -(2.18*10^-¹⁸J)
Z²

\left( \frac { 1 } { n _ { f } ^ { 2 } } - \frac { 1 } { n _ { i } ^ { 2 } } \right.

Which of the following species will have the longest wavelength emission line for the transition between the n_i = 2 and n_f = 1 levels?

Quizplus · Accepted Answer

The longest wavelength corresponds to the smallest energy change. Since the energy change is proportional to Z², the species with the smallest Z (hydrogen, Z=1) will have the smallest energy change and thus the longest wavelength.

The Change in Energy of a One-Electron Atom or Ion Δ\DeltaΔ

The Change in Energy of a One-Electron Atom or Ion $\Delta$