Evidence for electron shells and subshells from spectra and ionisation energies

Orbitals and electron capacity of s, p, and d subshells

Photoelectron spectroscopy as evidence for electron subshells

Energy level diagrams and rules for filling electron subshells

Writing subshell notation for electron configurations

Noble gas (core) notation for electron configurations

Writing the electron configuration of boron using subshell notation

Writing the electron configuration for calcium using subshells

Writing the electron configuration for the fluoride ion F-

Writing the electron configuration for the Mg2+ ion

Drawing the energy level diagram for aluminium

Filling the energy level diagram for neon

Writing the electron configuration for the oxide ion (O2-)

Writing the electron configuration for arsenic using an energy level diagram

Writing beryllium's electron configuration in noble gas notation

Writing the electron configuration for the N3- ion

Writing noble gas notation for the bromide ion (Br⁻)

Writing full and noble gas core notation for selenium