Periodic Table with Electron Configuration

Walk along the rows up to your element. Each row you cross fills an s subshell (groups 1–2), then the d subshell one shell lower (groups 3–12, the d-block), then the p subshell (groups 13–18). The f-block rows fill f subshells two shells lower. The block you land in tells you which subshell the last electron went into.

A shorthand that replaces the inner electrons with the symbol of the previous noble gas in brackets. Sodium, 1s² 2s² 2p⁶ 3s¹, becomes [Ne] 3s¹.

In the first transition series, chromium ([Ar] 3d⁵ 4s¹) and copper ([Ar] 3d¹⁰ 4s¹). Heavier exceptions include Nb, Mo, Ru, Rh, Pd, Ag, Pt, Au and several lanthanides and actinides. They are marked in the list below.