• This section has been deprecated; due to the bewildering variety of slightly different categories in the literature and disagreement on their boundaries, a strict scheme based on blocks has been adopted as of January 2021.

• Note: as of 17 August 2013, the English wikipedia has changed categorisation and background colors of nonmetal elements. Below is the new categorisation scheme. Differences are about these old categories: "other nonmetal", "halogen", "post-transition metals"

Nonmetals are subdevided in diatomic nonmetals, polyatomic nonmetals (and noble gases, unchanged). The category other/poor metals is renamed into post-transition metals without further changes. This is the new scheme:

• See for example: {{compact extended periodic table}}
• Example {{Periodic table (32 columns, micro)}}, extended:

Earlier categorisation & color scheme for the English wikipedia (before 17 August 2013)

Metal Metalloid #cccc99 Nonmetal unknown chemical properties #e8e8e8 [oldnote 1] Alkali metal #ff9d9d Alkaline earth metal #ffdead Inner transition metal Transition metal #ffc0c0 Post-​transition metal #cccccc N Other Nonmetal #a0ffa0 N Halogen #ffff99 Noble gas #c0ffff Lanthanide #ffbfff Actinide #ff99cc Superactinide [oldnote 2] Eka-​superactinide [oldnote 2] predicted #d8bcbc predicted #ffecd3 [oldnote 2] [oldnote 2] predicted #d1ddff predicted #c6dd9d predicted #ffe2e2 predicted #d8d8d8 predicted #e2e2aa predicted #D3ffd3 predicted #ffffff predicted #ddffff ^ Unknown chemical properties (grey) may be used instead of predicted ^ a b c d Situation does not arise

When a reduced category set, or more general category set, is used, below are their color legends. It is unadvised to use different category levels (different legend rows) in a single table.

(As of December 2012)