Massa atom relatif: Perbedaan antara revisi

Istilah ini biasanya digunakan juga untuk merujuk pada '''bobot atom relatif''' yang dipublikasikan secara berkala oleh [[International Union of Pure and Applied Chemistry]] (IUPAC).<ref>The latest edition is {{cite journal | author = [[International Union of Pure and Applied Chemistry]] | url = http://www.iupac.org/publications/pac/2006/pdf/7811x2051.pdf | title = Atomic Weights of the Elements 2005 | journal = [[Pure and Applied Chemistry|Pure Appl. Chem.]] | volume = 78 | issue = 11 | pages = 2051–66 | doi = 10.1351/pac200678112051 | year = 2006}}</ref><ref>The updated list of standard atomic weights is expected to be formally published in late 2008. The IUPAC Commission on Isotopic Abundances and Atomic Weights [http://www.iupac.org/objID/Note/nt50112469625981329917907 announced] {{Webarchive|url=https://web.archive.org/web/20090204154231/http://www.iupac.org/objID/Note/nt50112469625981329917907 |date=2009-02-04 }} in August 2007 that the standard atomic weights of the following elements would be revised (new figures quoted here): [[lutetium]] 174.9668(1); [[molybdenum]] 95.96(2); [[nickel]] 58.6934(4); [[ytterbium]] 173.054(5); [[zinc]] 65.38(2). The recommended value for the isotope amount ratio of {{sup|40}}Ar/{{sup|36}}Ar (which could be useful as a [[Scientific control|control measurement]] in [[argon–argon dating]]) was also changed from 296.03(53) to 298.56(31).</ref> Daftar bobot atom standar dapat ditemukan secara meluas dalam [[buku pelajaran]] kimia, katalog-katalog komersial, dan papan informasi di laboratorium kimia. Penggunaan kata "berat atom" telah mengundang banyak kontroversi, paling tidak sejak tahun 1960-an<ref name="IUPAChist">{{cite journal | first = P. | last = de Bièvre | coauthors = Peiser, H.S. | year = 1992 | title = 'Atomic Weight'—The Name, Its History, Definition, and Units | url = http://www.iupac.org/publications/pac/1992/pdf/6410x1535.pdf | journal = [[Pure and Applied Chemistry|Pure Appl. Chem.]] | volume = 64 | issue = 10 | pages = 1535–43 | doi = 10.1351/pac199264101535}}</ref> (lihat bawah).

Bobot atom dihitung dari pengukuran nilai massa atom relatif (tiap-tiap [[nuklida]]) dan [[komposisi isotop]]. Nilai massa atom relatif yang sangat akurat dapat ditemukan dengan bebas<ref name="NIST">[[National Institute of Standards and Technology]]. [http://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=&ascii=html&isotype=some Atomic Weights and Isotopic Compositions for All Elements].</ref><ref name="AME2003">{{AME 2003}}</ref> untuk hampir semua nuklida non-radioaktif, namun komposisi isotop sulit untuk dihitung secara tepat dan tergantung pada variasi antar sampel.<ref name="TICE1997">{{AtWt TICE 1997}}</ref><ref name="IAvar">{{AtWt IAV}}</ref>