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Group (periodic table)

Group (periodic table)

In chemistry, a group (also known as a family[1]) is a column of elements in the periodic table of the chemical elements. There are 18 numbered groups in the periodic table, and the f-block columns (between groups 3 and 4) are not numbered. The elements in a group have similar physical or chemical characteristics of the outermost electron shells of their atoms (i.e., the same core charge), as most chemical properties are dominated by the orbital location of the outermost electron.

There are three systems of group numbering for the groups, that often assign the same number to different groups. The modern numbering "group 1" to "group 18" has been recommended by the International Union of Pure and Applied Chemistry (IUPAC) since about 1990. It replaces two older incompatible naming schemes, used by the Chemical Abstract Service (CAS, more popular in the U. S.), and by IUPAC before 1990 (more popular in Europe). The system of eighteen groups is generally accepted by the chemistry community, but some dissent exists about membership of several elements. Disagreements mostly involve elements number 1 and 2 (hydrogen and helium), as well as inner transition metals.

Groups may also be identified by their topmost element or have a specific name. For example, group 16 is variously described as the "oxygen group" and as the "chalcogens". However, iron group usually does not mean "group 8". In chemistry it may mean either iron, cobalt, and nickel, or some other set of elements with similar chemical properties. In astrophysics and nuclear physics, it usually means those three plus chromium and manganese.

Group names

In history, several sets of group names have been used:[2][3]

IUPAC group1a23bb456789101112131415161718
Trivial nameH and Alkali metalsrAlkaline earth metalsrCoin­age metalsTrielsTetrelsPnicto­gensrChal­co­gensrHalo­gensrNoble gasesr
Name by elementrLith­ium groupBeryl­lium groupScan­dium groupTitan­ium groupVana­dium groupChro­mium groupMan­ga­nese groupIron groupCo­balt groupNickel groupCop­per groupZinc groupBoron groupCar­bon groupNitro­gen groupOxy­gen groupFluor­ine groupHelium or Neon group
Period 1 H He
Period 2LiBeBCNOFNe
Period 3NaMgAlSiPSClAr
Period 4KCaScTiVCrMnFeCoNiCuZnGaGeAsSeBrKr
Period 5RbSrYZrNbMoTcRuRhPdAgCdInSnSbTeIXe
Period 6CsBaLaCe–LuHfTaWReOsIrPtAuHgTlPbBiPoAtRn
Period 7FrRaAcTh–LrRfDbSgBhHsMtDsRgCnNhFlMcLvTsOg
by element
trivial name
Other trivial name
Group 1IAIA
lithium family
alkali metals*
Group 2IIAIIAberyllium familyalkaline earth metals*
Group 3IIIAIIIBscandium family
Group 4IVAIVBtitanium family
Group 5VAVBvanadium family
Group 6VIAVIBchromium family
Group 7VIIAVIIBmanganese family
Group 8VIIIVIIIBiron family
Group 9VIIIVIIIBcobalt family
Group 10VIIIVIIIBnickel family
Group 11IBIBcopper familycoinage metals
Group 12IIBIIBzinc family
Group 13IIIBIIIAboron familytriels from Greek tri (three, III)[5][6]
Group 14IVBIVAcarbon familytetrels from Greek tetra (four, IV)[5][6]
Group 15VBVAnitrogen familypnictogens*pentels from Greek penta (five, V)[6]
Group 16VIBVIAoxygen familychalcogens*
Group 17VIIBVIIAfluorine familyhalogens*
Group 180VIIIAheliumfamily
orneon family
noble gases*

Some other names have been proposed and used without gaining wide acceptance: "volatile metals" for group 12; "icosagens" for group 13;[7] "crystallogens",[5] "adamantogens",[8] and "merylides" for group 14; and "aerogens" for group 18.[6]

CAS and old IUPAC numbering (A/B)

Two earlier group number systems exist: CAS (Chemical Abstracts Service) and old IUPAC. Both use numerals (Arabic or Roman) and letters A and B. Both systems agree on the numbers. The numbers indicate approximately the highest oxidation number of the elements in that group, and so indicate similar chemistry with other elements with the same numeral. The number proceeds in a linearly increasing fashion for the most part, once on the left of the table, and once on the right (see List of oxidation states of the elements), with some irregularities in the transition metals. However, the two systems use the letters differently. For example, potassium (K) has one valence electron. Therefore, it is located in group 1. Calcium (Ca) is in group 2, for it contains two valence electrons.

In the old IUPAC system the letters A and B were designated to the left (A) and right (B) part of the table, while in the CAS system the letters A and B are designated to main group elements (A) and transition elements (B). The old IUPAC system was frequently used in Europe, while the CAS is most common in America. The new IUPAC scheme was developed to replace both systems as they confusingly used the same names to mean different things. The new system simply numbers the groups increasingly from left to right on the standard periodic table. The IUPAC proposal was first circulated in 1985 for public comments,[2] and was later included as part of the 1990 edition of the Nomenclature of Inorganic Chemistry.[9]

See also

  • Period (periodic table)


Citation Linkwww.shmoop.com"The Periodic Table Terms". www.shmoop.com. Retrieved 2018-09-15.
Sep 30, 2019, 10:42 AM
Citation Link//doi.org/10.1351%2Fpac198860030431Fluck, E. (1988). "New Notations in the Periodic Table" (PDF). Pure Appl. Chem. IUPAC. 60 (3): 431–436. doi:10.1351/pac198860030431. Retrieved 24 March 2012.
Sep 30, 2019, 10:42 AM
Citation Linkold.iupac.orgIUPAC (2005). "Nomenclature of inorganic chemistry" (PDF).
Sep 30, 2019, 10:42 AM
Citation Linkiupac.org"The constitution of group 3 of the periodic table". IUPAC. 2015-12-18.
Sep 30, 2019, 10:42 AM
Citation Link//doi.org/10.1016%2Fj.seppur.2018.10.027Liu, Ning; Lu, Na; Su, Yan; Wang, Pu; Quan, Xie (2019). "Fabrication of g-C3N4/Ti3C2 composite and its visible-light photocatalytic capability for ciprofloxacin degradation" (PDF). Separation and Purification Technology. 211: 782–789. doi:10.1016/j.seppur.2018.10.027. Retrieved 17 August 2019.
Sep 30, 2019, 10:42 AM
Citation Link//doi.org/10.1007%2F978-3-540-73962-3Rich, Ronald (2007). Inorganic Reactions in Water. Springer. pp. 307, 327, 363, 475. doi:10.1007/978-3-540-73962-3. ISBN 9783540739616.
Sep 30, 2019, 10:42 AM
Citation Linkopenlibrary.orgGreenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 227. ISBN 978-0-08-037941-8.
Sep 30, 2019, 10:42 AM
Citation Linkwww.che.uc.eduW. B. Jensen, The Periodic Law and Table
Sep 30, 2019, 10:42 AM
Citation Linkopenlibrary.orgLeigh, G. J. Nomenclature of Inorganic Chemistry: Recommendations 1990. Blackwell Science, 1990. ISBN 0-632-02494-1.
Sep 30, 2019, 10:42 AM
Citation Linkwww.shmoop.com"The Periodic Table Terms"
Sep 30, 2019, 10:42 AM
Citation Linkwww.iupac.org"New Notations in the Periodic Table"
Sep 30, 2019, 10:42 AM
Citation Linkdoi.org10.1351/pac198860030431
Sep 30, 2019, 10:42 AM
Citation Linkold.iupac.org"Nomenclature of inorganic chemistry"
Sep 30, 2019, 10:42 AM
Citation Linkiupac.org"The constitution of group 3 of the periodic table"
Sep 30, 2019, 10:42 AM
Citation Linkwww.researchgate.net"Fabrication of g-C3N4/Ti3C2 composite and its visible-light photocatalytic capability for ciprofloxacin degradation"
Sep 30, 2019, 10:42 AM
Citation Linkdoi.org10.1016/j.seppur.2018.10.027
Sep 30, 2019, 10:42 AM
Citation Linkdoi.org10.1007/978-3-540-73962-3
Sep 30, 2019, 10:42 AM
Citation Linkwww.che.uc.eduThe Periodic Law and Table
Sep 30, 2019, 10:42 AM
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