Lesson: Electron Energy Level Transitions

Plan

Objectives

Students will be able to

recall that the energy level an electron is in is denoted by the principal quantum number, ,
recall that the lowest possible value for is 1 and that this represents the most strongly bound electrons,
recall that the state is called the ground state,
recall that increases for higher energy levels and that the greater the value of , the less strongly bound an electron is,
recall that the term electron energy level transition refers to an electron moving between two energy levels,
calculate the energy difference between two energy levels given the binding energy of each energy level,
calculate the frequency or wavelength of the emitted or absorbed photon based on the energy levels that an electron transitions between (using ),
recall that certain groups of transitions have certain names (e.g., Lyman series, Balmer series, Paschen series).

Prerequisites

Students should already be familiar with

the idea that electrons in atoms occupy discrete energy levels,
the idea that when an electron moves from a higher energy level to a lower energy level, a photon is emitted,
the idea that an electron can move from a lower energy level to a higher energy level by absorbing a photon,
the electron volt (eV) as a unit of energy,
how to convert between joules (J) and electron volts (eV).

Exclusions

Students will not cover

the other quantum numbers (, , ),
subshells,
the energy level configuration for any element other than hydrogen,
mean excited state lifetimes,
the difference between stimulated and spontaneous emissions of photons,
the quantum mechanical origins of discrete energy levels.

Video

16:44

Worksheet

Q1:

The diagram shows the binding energy of each energy level of a hydrogen atom. If an electron is in the ground state, what frequency of photon must it absorb in order to move to the energy level ? Use a value of eV⋅s for the Planck constant. Give your answer in scientific notation to two decimal places.

Q2:

The diagram shows the emission spectrum of hydrogen for the visible part of the electromagnetic spectrum. The table shows the binding energies for the different energy levels of a hydrogen atom.

Energy Level	1	2	3	4	5
Binding Energy (eV)

Between which two energy levels must an electron transition in order to produce the emission line marked on the diagram?

Q3:

The diagram shows four possible transitions that an electron can make between the energy levels of a hydrogen atom. What name is given to this series of transitions?

Preview