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; the 14 f-block columns, between groups 2 and 3, 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), because most chemical properties are dominated by the orbital location of the outermost electron.
In the periodic table of the elements, each column is a group.
There are three systems of group numbering for the groups; the same number may be assigned to different groups depending on the system being used. The modern numbering system of "group 1" to "group 18" has been recommended by the International Union of Pure and Applied Chemistry (IUPAC) since 1988. It replaces two older incompatible naming schemes, used by the Chemical Abstract Service (CAS, more popular in the United States), and by IUPAC before 1988 (more popular in Europe). The system of eighteen groups is generally accepted by the chemistry community, but some dissent exists about membership of elements number 1 and 2 (hydrogen and helium). Similar variation on the inner transition metals continues to exist in textbooks, although the correct positioning has been known since 1948 and was twice endorsed by IUPAC in 1988 (together with the 1–18 numbering) and 2021.
Groups may also be identified using their topmost element, or have a specific name. For example, group 16 is also described as the "oxygen group" and as the "chalcogens". An exception is the "iron group", which usually refers to "group 8", but in chemistry may also mean iron, cobalt, and nickel, or some other set of elements with similar chemical properties. In astrophysics and nuclear physics, it usually refers to iron, cobalt, nickel, chromium, and manganese.
Modern group names are numbers 1–18, with the 14 f-block columns remaining unnumbered (together making the 32 columns in the periodic table). Also, trivial names (like halogens) are common. In history, several sets of group names have been used, based on Roman numberings I–VIII, and "A" and "B" suffixes.[2][3]
a Group 1 is composed of hydrogen (H) and the alkali metals. Elements of the group have one s-electron in the outer electron shell. Hydrogen is not considered to be an alkali metal as it is not a metal, though it is more analogous to them than any other group. This makes the group somewhat exceptional. b The 14 f-block groups (columns) do not have a group number. c The correct composition of group 3 is scandium (Sc), yttrium (Y), lutetium (Lu), and lawrencium (Lr), as shown here: this is endorsed by 1988[4] and 2021[5] IUPAC reports on the question. General inorganic chemistry texts often put scandium (Sc), yttrium (Y), lanthanum (La), and actinium (Ac) in group 3, so that Ce–Lu and Th–Lr become the f-block between groups 3 and 4; this was based on incorrectly measured electron configurations from history,[6] and Lev Landau and Evgeny Lifshitz already considered it incorrect in 1948.[7] Arguments can still occasionally be encountered in the contemporary literature purporting to defend it, but most authors consider them logically inconsistent.[8][9][10] Some sources follow a compromise that puts La–Lu and Ac–Lr as the f-block rows (despite that giving 15 f-block elements in each row, which contradicts quantum mechanics), leaving the heavier members of group 3 ambiguous.[5] See also Group 3 element#Composition. d Group 18, the noble gases, were not discovered at the time of Mendeleev's original table. Later (1902), Mendeleev accepted the evidence for their existence, and they could be placed in a new "group 0", consistently and without breaking the periodic table principle. r Group name as recommended by IUPAC.
^fCoinage metals: authors differ on whether roentgenium (Rg) is considered a coinage metal. It is in group 11, like the other coinage metals, and is expected to be chemically similar to gold.[17] On the other hand, being extremely radioactive and short-lived, it cannot actually be used for coinage as the name suggests, and on that basis it is sometimes excluded.[18]
^btriels (group 13), from Greek tri: three, III[13][16]
^ctetrels (group 14), from Greek tetra: four, IV[13][16]
^npentel (group 15), from Greek penta: five, V[16]
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.[19]
Non-columnwise groups
While groups are defined to be columns in the periodic table, as described above, there are also sets of elements named "group" that are not a column:
^ abFluck, E. (1988). "New Notations in the Periodic Table" (PDF). Pure Appl. Chem.IUPAC. 60 (3): 431–436. doi:10.1351/pac198860030431. S2CID 96704008. Retrieved 24 March 2012.
^IUPAC (2005). "Nomenclature of inorganic chemistry" (PDF).
^Fluck, E. (1988). "New Notations in the Periodic Table" (PDF). Pure Appl. Chem.60 (3): 431–436. doi:10.1351/pac198860030431. S2CID 96704008. (PDF) from the original on 25 March 2012. Retrieved 24 March 2012.
^ abScerri, Eric (18 January 2021). "Provisional Report on Discussions on Group 3 of the Periodic Table" (PDF). Chemistry International. 43 (1): 31–34. doi:10.1515/ci-2021-0115. S2CID 231694898. (PDF) from the original on 13 April 2021. Retrieved 9 April 2021.
^William B. Jensen (1982). "The Positions of Lanthanum (Actinium) and Lutetium (Lawrencium) in the Periodic Table". J. Chem. Educ. 59 (8): 634–636. Bibcode:1982JChEd..59..634J. doi:10.1021/ed059p634.
^Jensen, William B. (2015). "The positions of lanthanum (actinium) and lutetium (lawrencium) in the periodic table: an update". Foundations of Chemistry. 17: 23–31. doi:10.1007/s10698-015-9216-1. S2CID 98624395. from the original on 30 January 2021. Retrieved 28 January 2021.
^Scerri, Eric (2009). "Which Elements Belong in Group 3?". Journal of Chemical Education. 86 (10): 1188. doi:10.1021/ed086p1188. Retrieved 1 January 2023.
^Chemey, Alexander T.; Albrecht-Schmitt, Thomas E. (2019). "Evolution of the periodic table through the synthesis of new elements". Radiochimica Acta. 107 (9–11): 1–31. doi:10.1515/ract-2018-3082.
^Simmons, L. M. (1947). "A modification of the periodic table". Journal of Chemical Education. 24 (12): 588–591. doi:10.1021/ed024p588.
^ abcLiu, 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". Separation and Purification Technology. 211: 782–789. doi:10.1016/j.seppur.2018.10.027. S2CID 104746665. Retrieved 17 August 2019.
^Jensen, William B. (2000). (PDF). Archived from the original (PDF) on 2020-11-10. Retrieved 10 December 2022.
^Fernelius, W. C.; Loening, Kurt; Adams, Roy M. (1971). "Names of groups and elements". Journal of Chemical Education. 48 (11): 730–731. doi:10.1021/ed048p730.
^ abcdRich, Ronald (2007). Inorganic Reactions in Water. Springer. pp. 307, 327, 363, 475. doi:10.1007/978-3-540-73962-3. ISBN9783540739616.
^Conradie, Jeanet; Ghosh, Abhik (2019). "Theoretical Search for the Highest Valence States of the Coinage Metals: Roentgenium Heptafluoride May Exist". Inorganic Chemistry. 58 (13): 8735–8738. doi:10.1021/acs.inorgchem.9b01139. PMID 31203606. S2CID 189944098.
^Grochala, Wojciech; Mazej, Zoran (2015). "Chemistry of silver(II): a cornucopia of peculiarities". Philosophical Transactions of the Royal Society A. 373 (2037). doi:10.1098/rsta.2014.0179. PMID 25666068. S2CID 45589426.
^Leigh, G. J. Nomenclature of Inorganic Chemistry: Recommendations 1990. Blackwell Science, 1990. ISBN0-632-02494-1.
Further reading
Scerri, E. R. (2007). The periodic table, its story and its significance. Oxford University Press. ISBN978-0-19-530573-9.
April 27, 2023
group, periodic, table, chemistry, group, also, known, family, column, elements, periodic, table, chemical, elements, there, numbered, groups, periodic, table, block, columns, between, groups, numbered, elements, group, have, similar, physical, chemical, chara. 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 the 14 f block columns between groups 2 and 3 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 because most chemical properties are dominated by the orbital location of the outermost electron In the periodic table of the elements each column is a group There are three systems of group numbering for the groups the same number may be assigned to different groups depending on the system being used The modern numbering system of group 1 to group 18 has been recommended by the International Union of Pure and Applied Chemistry IUPAC since 1988 It replaces two older incompatible naming schemes used by the Chemical Abstract Service CAS more popular in the United States and by IUPAC before 1988 more popular in Europe The system of eighteen groups is generally accepted by the chemistry community but some dissent exists about membership of elements number 1 and 2 hydrogen and helium Similar variation on the inner transition metals continues to exist in textbooks although the correct positioning has been known since 1948 and was twice endorsed by IUPAC in 1988 together with the 1 18 numbering and 2021 Groups may also be identified using their topmost element or have a specific name For example group 16 is also described as the oxygen group and as the chalcogens An exception is the iron group which usually refers to group 8 but in chemistry may also mean iron cobalt and nickel or some other set of elements with similar chemical properties In astrophysics and nuclear physics it usually refers to iron cobalt nickel chromium and manganese Contents 1 Group names 1 1 List of group names 2 CAS and old IUPAC numbering A B 3 Non columnwise groups 4 References 5 Further readingGroup names EditModern group names are numbers 1 18 with the 14 f block columns remaining unnumbered together making the 32 columns in the periodic table Also trivial names like halogens are common In history several sets of group names have been used based on Roman numberings I VIII and A and B suffixes 2 3 vteGroups in the periodic tableIUPAC group 1a 2 b 3c 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18Mendeleev I VIII IA IIA IIIB IVB VB VIB VIIB VIIIB IB IIB IIIB IVB VB VIB VIIB dCAS US A B A IA IIA IIIB IVB VB VIB VIIB VIIIB IB IIB IIIA IVA VA VIA VIIA VIIIAOld IUPAC Europe A B IA IIA IIIA IVA VA VIA VIIA VIIIB IB IIB IIIB IVB VB VIB VIIB 0Trivial namer H and alkali metals alkaline earth metals triels tetrels pnicto gens chal co gens halo gens noble gasesName by elementr lith ium group beryl lium group scan dium group titan ium group vana dium group chro mium group man ga nese group iron group co balt group nickel group cop per group zinc group boron group car bon group nitro gen group oxy gen group fluor ine group helium or neon groupPeriod 1 H HePeriod 2 Li Be B C N O F NePeriod 3 Na Mg Al Si P S Cl ArPeriod 4 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br KrPeriod 5 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I XePeriod 6 Cs Ba La Yb Lu Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At RnPeriod 7 Fr Ra Ac No Lr Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Oga Group 1 is composed of hydrogen H and the alkali metals Elements of the group have one s electron in the outer electron shell Hydrogen is not considered to be an alkali metal as it is not a metal though it is more analogous to them than any other group This makes the group somewhat exceptional b The 14 f block groups columns do not have a group number c The correct composition of group 3 is scandium Sc yttrium Y lutetium Lu and lawrencium Lr as shown here this is endorsed by 1988 4 and 2021 5 IUPAC reports on the question General inorganic chemistry texts often put scandium Sc yttrium Y lanthanum La and actinium Ac in group 3 so that Ce Lu and Th Lr become the f block between groups 3 and 4 this was based on incorrectly measured electron configurations from history 6 and Lev Landau and Evgeny Lifshitz already considered it incorrect in 1948 7 Arguments can still occasionally be encountered in the contemporary literature purporting to defend it but most authors consider them logically inconsistent 8 9 10 Some sources follow a compromise that puts La Lu and Ac Lr as the f block rows despite that giving 15 f block elements in each row which contradicts quantum mechanics leaving the heavier members of group 3 ambiguous 5 See also Group 3 element Composition d Group 18 the noble gases were not discovered at the time of Mendeleev s original table Later 1902 Mendeleev accepted the evidence for their existence and they could be placed in a new group 0 consistently and without breaking the periodic table principle r Group name as recommended by IUPAC List of group names Edit IUPACname OldIUPAC Europe Old CASname U S Nameby element group or family IUPACrecommendedtrivial name Other namesGroup 1 IA IA lithium group hydrogen and alkali metals lithium group excludes hydrogenGroup 2 IIA IIA beryllium group alkaline earth metalsGroup 3 IIIA IIIB scandium groupGroup 4 IVA IVB titanium groupGroup 5 VA VB vanadium groupGroup 6 VIA VIB chromium groupGroup 7 VIIA VIIB manganese groupGroup 8 VIII VIIIB iron groupGroup 9 VIII VIIIB cobalt groupGroup 10 VIII VIIIB nickel groupGroup 11 IB IB copper group Sometimes called coinage metals but the set is arbitraryfGroup 12 IIB IIB zinc group volatile metals 11 Group 13 IIIB IIIA boron group trielsb icosagens 12 Group 14 IVB IVA carbon group tetrelsc crystallogens 13 adamantogens 14 merylides 15 Group 15 VB VA nitrogen group pnictogenspentelsnGroup 16 VIB VIA oxygen group chalcogensGroup 17 VIIB VIIA fluorine group halogensGroup 18 0 VIIIA helium groupor neon group noble gases aerogens 16 f Coinage metals authors differ on whether roentgenium Rg is considered a coinage metal It is in group 11 like the other coinage metals and is expected to be chemically similar to gold 17 On the other hand being extremely radioactive and short lived it cannot actually be used for coinage as the name suggests and on that basis it is sometimes excluded 18 b triels group 13 from Greek tri three III 13 16 c tetrels group 14 from Greek tetra four IV 13 16 n pentel group 15 from Greek penta five V 16 CAS and old IUPAC numbering A B EditTwo 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 19 Non columnwise groups EditWhile groups are defined to be columns in the periodic table as described above there are also sets of elements named group that are not a column Platinum group Hydrogen HeliumLithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine NeonSodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine ArgonPotassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine KryptonRubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine XenonCaesium 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 RadonFrancium 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 Iron group Hydrogen HeliumLithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine NeonSodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine ArgonPotassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine KryptonRubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine XenonCaesium 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 RadonFrancium 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 Similar sets noble metals coinage metals precious metals refractory metals References Edit The Periodic Table Terms www shmoop com Retrieved 2018 09 15 a b Fluck E 1988 New Notations in the Periodic Table PDF Pure Appl Chem IUPAC 60 3 431 436 doi 10 1351 pac198860030431 S2CID 96704008 Retrieved 24 March 2012 IUPAC 2005 Nomenclature of inorganic chemistry PDF Fluck E 1988 New Notations in the Periodic Table PDF Pure Appl Chem 60 3 431 436 doi 10 1351 pac198860030431 S2CID 96704008 Archived PDF from the original on 25 March 2012 Retrieved 24 March 2012 a b Scerri Eric 18 January 2021 Provisional Report on Discussions on Group 3 of the Periodic Table PDF Chemistry International 43 1 31 34 doi 10 1515 ci 2021 0115 S2CID 231694898 Archived PDF from the original on 13 April 2021 Retrieved 9 April 2021 William B Jensen 1982 The Positions of Lanthanum Actinium and Lutetium Lawrencium in the Periodic Table J Chem Educ 59 8 634 636 Bibcode 1982JChEd 59 634J doi 10 1021 ed059p634 L D Landau E M Lifshitz 1958 Quantum Mechanics Non Relativistic Theory Vol 3 1st ed Pergamon Press pp 256 7 Jensen William B 2015 The positions of lanthanum actinium and lutetium lawrencium in the periodic table an update Foundations of Chemistry 17 23 31 doi 10 1007 s10698 015 9216 1 S2CID 98624395 Archived from the original on 30 January 2021 Retrieved 28 January 2021 Scerri Eric 2009 Which Elements Belong in Group 3 Journal of Chemical Education 86 10 1188 doi 10 1021 ed086p1188 Retrieved 1 January 2023 Chemey Alexander T Albrecht Schmitt Thomas E 2019 Evolution of the periodic table through the synthesis of new elements Radiochimica Acta 107 9 11 1 31 doi 10 1515 ract 2018 3082 Simmons L M 1947 A modification of the periodic table Journal of Chemical Education 24 12 588 591 doi 10 1021 ed024p588 Greenwood Norman N Earnshaw Alan 1997 Chemistry of the Elements 2nd ed Butterworth Heinemann p 227 ISBN 978 0 08 037941 8 a b c Liu 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 Separation and Purification Technology 211 782 789 doi 10 1016 j seppur 2018 10 027 S2CID 104746665 Retrieved 17 August 2019 Jensen William B 2000 The Periodic Law and Table PDF Archived from the original PDF on 2020 11 10 Retrieved 10 December 2022 Fernelius W C Loening Kurt Adams Roy M 1971 Names of groups and elements Journal of Chemical Education 48 11 730 731 doi 10 1021 ed048p730 a b c d Rich Ronald 2007 Inorganic Reactions in Water Springer pp 307 327 363 475 doi 10 1007 978 3 540 73962 3 ISBN 9783540739616 Conradie Jeanet Ghosh Abhik 2019 Theoretical Search for the Highest Valence States of the Coinage Metals Roentgenium Heptafluoride May Exist Inorganic Chemistry 58 13 8735 8738 doi 10 1021 acs inorgchem 9b01139 PMID 31203606 S2CID 189944098 Grochala Wojciech Mazej Zoran 2015 Chemistry of silver II a cornucopia of peculiarities Philosophical Transactions of the Royal Society A 373 2037 doi 10 1098 rsta 2014 0179 PMID 25666068 S2CID 45589426 Leigh G J Nomenclature of Inorganic Chemistry Recommendations 1990 Blackwell Science 1990 ISBN 0 632 02494 1 Further reading EditScerri E R 2007 The periodic table its story and its significance Oxford University Press ISBN 978 0 19 530573 9 Retrieved from https en wikipedia org w index php title Group periodic table amp oldid 1140166412, wikipedia, wiki, book, books, library,
