Wikipedia:WikiProject Elements/Guidelines

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Article structure guidelines

With a few suggestions for unified phrasings. (Note that the coding of headings is different only for this illustration, the usual article editing guidelines apply.) (_ElementDescription_ is something like: "silvery and ductile member of the post-transition metal group of chemical elements.")

See also: Wikipedia:Manual of Style (chemistry)/Elements/draft

__ is a _ElementDescription_. Its symbol is __ and its atomic number is __.

Or alternatively for short-lived synthetic elements:

__ is a synthetic element in the periodic table that has the symbol __ and atomic number __.

Characteristics

Physical

Describe the basic properties of the element (not its compounds) in everday life: physical state (we assume STP), electrical/thermal conductivity, color. Follow this part with more complex content such as ionization potentials, electron configuration, heat of vapourization, etc. If there a lot to say about any one item, say allotropes, then a separate ===Allotropes=== subsection would probably be helpful.

Chemical

Reactions of the element (principal compounds comprise a separate section). Reactions with water, air (corrosion), redox potential of the element.

Isotopes

Discuss isotopes per suggested boilerplate text below. If appropriate, also discuss nucleosynthesis in stars / nova.

Main article: Isotopes of X

Naturally occurring _ is composed of _ stable isotopes, _-_, _-_, and _-_, with _-_ being the most abundant (_% natural abundance). Out of these, _ are of use in NMR and EPR spectroscopy. _ radioisotopes have been characterized, with the most {abundant and/or stable} being _-_ with a half-life of _, _-_ with a half-life of _, and _-_ with a half-life of _. All of the remaining radioactive isotopes have half-lives that are less than _, and the majority of these have half lives that are less than _. This element also has _ nuclear isomers, with the longest-lived being _m-_ (t_½ _), _m-_ (t_½ _) and _m-_ (t_½ _). The nuclei of nuclear isomers exist in a delicate equilibrium or metastability due to at least one nucleon having an excited energy state.

The isotopes of _ range in mass number from _ to _ . The most common decay mode(s) of _ isotopes with mass numbers lower than the most abundant stable isotope, _-_, is/are [[{name of decay mode}]] /and [[{name of decay mode}]], primarily forming _ isotopes (_ protons) /and _ isotopes (_ protons) as decay products. The most common decay mode(s) for _ isotopes with mass numbers higher than _-_, are [[{name of decay mode}]] /and [[{name of decay mode}]]. primarily forming _ isotopes (_ protons) /and _ isotopes (_ protons) as decay products.

Occurrence

Amount of element in ... the solar system, earth, crust, water, atmosphere, humans and other organisms (as available and appropriate). Discuss ores and minerals, mentioning global reserves.

Production

Not needed for elements that are not extensively mined, refined or used. Mention mining amounts, extraction techniques and amount of pure element or other derivatives produced for industry each year here. Also mention any environmental/pollution issues associated with the processing.

Information about the price is usually placed at the bottom of this section. Specify as of when is the information. Where applicable, state purity or type and use relevant industry standard units for currency and amount (example: US$ per troy ounce for gold). Indicate trends and provide a link to a live source where possible. Information about many commodities is available at [1] for example.

Compounds

This section is longer than ===chemical characteristics=== above, which is largely restricted to the element (otherwise these sections are semi-redundant). Main binary compounds should be discussed; separating them by oxidation state. Comments on geometry, magnetism and a feel for the reactivity. Aqueous behavior toward bases and acids (i.e. the element-ATE ions). Where appropriate, separate section on organic/organometallic derivatives (for most elements, an article exists on "organo... compound", so {{main|organo...}} is indicated.

section with subsections and possibly a Main Article link to a "Compounds of ..." daughter article.

History

If the element was not known to the ancients, then mention who discovered it (and/or its oxide) and how (mention other contributors as well). If known by the ancients, then mention by what cultures, when first used (best evidence) and what the element was used for. Briefly mention major historical uses of the element and its major oxides (if applicable). Mention any notable use by alchemists and provide an image of alchemical symbol. A portrait of the discoverer should probably be included. Other major developments should be summarized such as technologies for the extraction or utilization.

Applications

Ranked in order of usage, ideally with graphic (pie-chart) showing use-fractions. Most real-world applications are prosaic and might not appeal to many academic editors. Most metals are used as the metals, not compounds. Laboratory reagents consume negligible amounts of production stream, so this content should not be allowed to dominate. Enumerating other niche uses similarly can overwhelm almost any article (e.g. copper is used to make door knobs). Avoid lists.

There's always some tension between the largest uses of an element, and how much to write about them. For example, 93% of world potassium production is for fertilizer, but 93% of the potassium#Applications should not be about fertilizer! Similarly, bio-centric/medicinal uses of an element merit attention well-beyond beyond their use-fractions.

Biological role

Approximately 20 elements are required by higher organisms. Discuss how the element is used in organisms (prominent enzymes/proteins) and how the element manifests itself. Discuss how a deficiency of the element affects health. Toxic effects should be placed in the ==Precautions== section.

Precautions

NFPA 704 safety square

Discuss toxic effects and amount needed to be toxic to humans and other organisms. Mention handling standards and notable accidents involving improper handling (if not already mentioned in ==History== section). Any mention of deliberate use as a toxin should go in the ==Applications== section. Particularly toxic elements should include an NFPA 704 diagram ("fire diamond", template {{NFPA 704}} box). Note that extensive toxicity and hazard material is available to casual editors, so this section is reserved for highly notable information, e.g. arsenic is highly toxic, but we do not discuss that combining sodium and water is dangerous (that would go into the chemical characteristics section).

Notes

Only needed if <ref group="note">explanatory note here</ref> is used to add inline footnotes to provide more detailed explanations that would otherwise disturb the flow of the prose. They are rarely needed.

References

Place <references/> here. This section will automatically list all inline citations using the <ref></ref> markup. Especially for articles on elements, references are reserved for texts, monographs, review series. Primary journals are cited mainly to illustrate points.

May include, not all links applicable everywhere:

Bibliography

References are mainly reserved for major texts, monographs, review series. Primary journals are cited mainly to illustrate points. List all multipage reference works that are cited multiple times on different pages here. Inline cites in the prose that reference works listed here need to indicate author's last name, year of publication and page number. Example: Weeks 1933, p. 22. The {{harvnb}} template could also be used to give. Weeks 1933, p. 22

• CRC contributors (2006). David R. Lide (ed.). Handbook of Chemistry and Physics (87th ed.). Boca Raton, Florida: CRC Press, Taylor & Francis Group. ISBN 0-8493-0487-3. {{cite book}}: |author= has generic name (help)
• Emsley, John (2001). Nature's Building Blocks: An A-Z Guide to the Elements. Oxford, England, UK: Oxford University Press. ISBN 0198503407.
• Stwertka, Albert (1998). Guide to the Elements (Revised ed.). Oxford University Press. ISBN 0-19-508083-1.
• Greenwood, N. N.; Earnshaw, A. (1997). Chemistry of the Elements (2nd ed.). Oxford: Butterworth-Heinemann. ISBN 0-7506-3365-4.
• {Author} (1968). Clifford A. Hampel (ed.). The Encyclopedia of the Chemical Elements. New York: Reinhold Book Corporation. LCCN 68-29938. {{cite book}}: |last= has generic name (help)
• Heiserman, David L. "Element 00: ElementName". Exploring Chemical Elements and their Compounds. New York: TAB Books. ISBN 0-8306-3018-X.
• Weeks, Mary Elvira (1933). The Discovery of the Elements. Easton, PA: Journal of Chemical Education. ISBN 0766138720.

- _

Notes on some common references

• Husted, Robert (2003-12-15). "ElementName". Periodic Table of the Elements. Los Alamos National Laboratory.

Even though this text was paid for by CA State and US Federal tax dollars, the UC Regents claims a restrictive copyright so it is not public domain and therefore cannot be copied. Instead, use it as any other reference. In addition, the LANL periodic table hasn't been touched since 1997 but it has won several awards.

• http://minerals.usgs.gov/minerals/pubs/commodity/{element_name,lowercase}/ USGS _

Statistics and Information This is public domain material and can be copied verbatim but it isn't available for every element. The text may also be under a different name. They sometimes combine entries, such as iron and steel. If nothing comes up, then look for the element at http://minerals.usgs.gov/minerals/pubs/commodity/ .

• http://wwwrcamnl.wr.usgs.gov/isoig/period/{element_symbol,lowercase}_iig.html USGS

Periodic Table - _ This is public domain isotope info and can be copied verbatim but it is very technical and usually only the first paragraph or two are useable at all (the focus of the USGS period table is hydrology and we needn't fill our period table with material that is that specialized). Not all elements are included in this source.

• van der Krogt, Peter (2005). "{ElementName}". Elementymology & Elements Multidict.

Can't be used directly because it is self-published work and thus not a reliable source, but a good starting point to get oriented about an elements discovery and naming. Any info obtained from that website must be independently verified and cited to the alternate, more reliable, source. Luckily, van der Krogt is pretty good and citing sources.

• http://www.columbia.edu/cu/chemistry/groups/parkin/mlxz.htm

Is a good and reliable starting point for the chemistry sections of transition metals.

• http://sis.nlm.nih.gov/sitemapsearch.html

Good for precautions issues.

• http://onlinelibrary.wiley.com/book/10.1002/14356007/homepage/WhatsNew.html

Ullman's Encyclopedia of Industrial Chemistry.

• http://www.roskill.com/

Is a good review for some metals and minerals.

Reference data pages

Any changes to the infobox data should be checked against these pages, and/or the available references should be expanded accordingly, so that the decision for or against certain values remains transparent and easily retraceable.

• List of data references for chemical elements

Previous data sources

The earlier guide for acquiring the data included these sources:

NOTE: struck items are explicitly no longer recommended for use for any data in element articles. When found, these references should be replaced by more reliable sources.

• http://www.WebElements.com/ for series, period, block, density, appearance, atomic weight, atomic/covalent/van der Waals radii, electron configuration, electrons per energy level, state of matter at STP, melting and boiling point at SP, molar volume, velocity of sound, ionization potentials.
• http://EnvironmentalChemistry.com/ for hardness (Mohs), oxidation states, crystal structure, heats of vaporization/fusion, vapor pressure, electronegativity, specific heat capacity, electrical conductivity, thermal conductivity, nuclides.

The recommendation regarding which nuclides should be included in the infobox table has been: "Choose all the stable forms and only a small selection of the most stable radioisotopes."

• http://chemlab.pc.maricopa.edu/periodic/periodic.html for "oxide is (...)", heats of vaporization/fusion (alternate source).
• http://www.allmeasures.com/Formulae/static/materials/ for velocity of sound (alternate source), specific heat capacity (alternate source).

Color standards

Link to superseded standards (2013) for historical reference purposes. Sandbh (talk) 04:20, 11 June 2017 (UTC)

Category

• 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:

Metal

Metalloid #cccc99

Nonmetal

unknown chemical properties #e8e8e8

Alkali metal #ff9d9d

Alkaline earth metal #ffdead

Inner transition metal

Transition metal #ffc0c0

post-​transition metal #cccccc

Polyatomic nonmetal #a1ffc3

Diatomic nonmetal #e7ff8f

Noble gas #c0ffff

Lanthanide #ffbfff

Actinide #ff99cc

Superactinide

Eka-​superactinide

predicted #d8bcbc

predicted #ffecd3

predicted #d1ddff

predicted #c6dd9d

predicted #ffe2e2

predicted #d8d8d8

predicted #e2e2aa

predicted #d0ffe1

predicted #f2ffc2

predicted #ddffff

Usage

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

Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson Ununennium Unbinilium Unquadtrium Unquadquadium Unquadpentium Unquadhexium Unquadseptium Unquadoctium Unquadennium Unpentnilium Unpentunium Unpentbium Unpenttrium Unpentquadium Unpentpentium Unpenthexium Unpentseptium Unpentoctium Unpentennium Unhexnilium Unhexunium Unhexbium Unhextrium Unhexquadium Unhexpentium Unhexhexium Unhexseptium Unhexoctium Unhexennium Unseptnilium Unseptunium Unseptbium Unbiunium Unbibium Unbitrium Unbiquadium Unbipentium Unbihexium Unbiseptium Unbioctium Unbiennium Untrinilium Untriunium Untribium Untritrium Untriquadium Untripentium Untrihexium Untriseptium Untrioctium Untriennium Unquadnilium Unquadunium Unquadbium

Earlier category scheme

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

Metal Metalloid #cccc99 Nonmetal unknown chemical properties #e8e8e8 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 Eka-​superactinide predicted #d8bcbc predicted #ffecd3 predicted #d1ddff predicted #c6dd9d predicted #ffe2e2 predicted #d8d8d8 predicted #e2e2aa predicted #D3ffd3 predicted #ffffff predicted #ddffff

Categories, reduced set

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.

Metal #eee8aa

Metalloid #cccc99

Nonmetal #b0e0e6

unknown chemical properties #e8e8e8

Alkali metal #ff9d9d

Alkaline earth metal #ffdead

Inner transition metal #d8bfd8

Transition metal #ffc0c0

post-transition metal #cccccc

Polyatomic nonmetal #a1ffc3

Diatomic nonmetal #e7ff8f

Noble gas #c0ffff

(As of December 2012)

Blocks

Block

s-block

g-block

f-block

d-block

p-block

Periodic table: block legend colors (enwiki, 25 July 2014) (The earlier set had the colors yellow-green swapped. That was during July 12–July 25 2014 only)
s	p	d	f	g
s-block Main Page #ff9999 HSV=0-40-100 red	p-block Main Page #fdff8c HSV=17-45-100 yellow	d-block Main Page #99ccff HSV=58-40-100 blue	f-block Main Page #9bff99 HSV=33-40-100 green	g-block* Main Page #fd99ff HSV=83-40-100 purple
Element is in block, theoretically or predicted:
s-block (predicted) Main Page #ffcccc	p-block (predicted) Main Page #ffffbf	d-block (predicted) Main Page #c7eeff	f-block (predicted) Main Page #cdffcc	g-block (predicted) Main Page #febfff
* Elements "in g-block" exist theoretically (predicted) only (this g-block darker color is not used, but here for color calculations)
Colors determined in HSV color space, numbers in %. Per column, Hue (the "H" in HSV) is kept; "S" is ~halved from 40%→20%, "V"=100%
Contrast is checked against black font and blue font (#0b0080, wiki bluelink color). All are: AA=OK, AAA=OK. Not checked against other font colors.
Version: introduced on enwiki 25 July 2014 (before, other color schemes were used on enwiki)
See also: commons:File:Periodic table blocks spdf (32 column).svg

State of matter, Occurrence

State of matter

Occurrence

Primordial  From decay  Synthetic Undiscovered Border shows natural occurrence of the element

Locator map image

Currently, the periodic table locator map images are no longer images, but instead are now clickable periodic tables with functionality similar to that of Template:Compact periodic table.