Previous ………. Next Topic >

Atomic Orbitals

Electrons occupy shells around the nucleus of an atom. Electrons move in every direction, but they are limited to their own area, or the orbit that the electron follows, which is what we call shells. Within each shell, there are subshells. Orbitals are regions within an atom that the electron will most likely occupy.

Orbitals within a shell are divided into subshells that have the same value of the angular quantum number . Chemists describe the shell and subshell in which an orbital belongs with a two-character code such as 2p or 4f. The orbital names s, p, d, and f stand for names given to groups of lines originally noted in the spectra of the alkali metals. These line groups are called sharp, principal, diffuse, and fundamental.

Lesson 1 (or “Day 1”) Material
Lesson 2 (or “Day 2”) Material
Lesson 3 (or “Day 3”) Material
Lesson 4 (or “Day 4”) Material

4:27 Writing Electron Configurations using periodic table “Blocks”

4:35 Quantum Mechanical Model

8:41 Quantum Numbers, Atomic Orbitals, and Electron Configurations


Compare Contrast and Debate

Background: In Chemistry,SPDF (used to label orbitals), stands for sharp, principal, diffuse and fundamental, respectively. The letters and words refer to the visual impression left by the fine structure of the spectral lines which occurs due to the first relativistic corrections, especially the spin-orbital interaction. Because we are so accustomed to “alphabetical order” in other disciplines – some have suggested that the letters would be easier to communicate through A,B,C,D.

  • Position A: SPDF makes sense – even though ABCD might initially be easier to recall, the “odd letter sequence” of SPDF should continue being used.
  • Position B: Perhaps SPDF could be introduced much later in advanced courses, but ABCD would make the subject much more approachable to new chemistry learners.

Resources Documents and Links

  • xx

Notes and Notices

Instructor Emphasis:

  • Science & Engineering Practice: Develop and use models.
  • Cross-Cutting Concept: Systems and System Models.