Lesson: Electron Energy Levels Physics

In this lesson, we will learn how to determine whether an electron shell of an atom is filled and which electron transitions are possible in a given atom.

Lesson Plan


Students will be able to

  • understand that electrons in atoms are in discrete energy levels,
  • understand electron shell diagrams:
    • understand that the nucleus is at the center,
    • understand that the circles around the center represent electron shells,
    • understand that the circles/shells/energy levels are counted from the innermost to the outermost,
  • understand the terms electron energy level and electron shell,
  • understand when an electron shell is filled:
    • know how many electrons can fit into each of the first three shells of an atom (2, 8, and 18),
    • identify whether a given shell is filled or unfilled from a diagram,
  • understand that the shells further out can carry more electrons than those further in,
  • identify elements based on electron shell configurations shown in diagrams for both neutral and charged atoms,
  • understand excited states:
    • understand the term excited states,
    • identify electrons in excited states,
  • understand electron transitions:
    • identify allowed transitions,
    • know that a photon is absorbed or emitted in a transition,
    • know that electron transitions between states that are further apart produce higher-energy photons.


Students should already be familiar with

  • the idea that atoms are made up of a nucleus surrounded by electrons,
  • the idea that atomic nuclei are made up of protons and neutrons,
  • the idea that protons are positively charged, neutrons are neutral, and electrons are negatively charged.


Students will not cover

  • calculating the energy of absorbed or emitted photons,
  • subshells,
  • mean excited state lifetime,
  • nuclear excited states/nuclear decays,
  • electron wave characteristics.

Lesson Video

Video Thumbnail

Sample Question Videos

  • 01:49
  • 02:35
  • 02:02

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