Template:Standard atomic weight of the elements

Standard atomic weight of the elements (IUPAC 2009–2021^{[ref 1]})

Z	Symbol	Name	Ar, standard	Abridged	Year changed
1	H	hydrogen	[1.00784, 1.00811]	1.0080±0.0002	2009
2	He	helium	4.002602±0.000002	4.0026±0.0001	1983
3	Li	lithium	[6.938, 6.997]	6.94±0.06	2009
4	Be	beryllium	9.0121831±0.0000005	9.0122±0.0001	2013
5	B	boron	[10.806, 10.821]	10.81±0.02	2009
6	C	carbon	[12.0096, 12.0116]	12.011±0.002	2009
7	N	nitrogen	[14.00643, 14.00728]	14.007±0.001	2009
8	O	oxygen	[15.99903, 15.99977]	15.999±0.001	2009
9	F	fluorine	18.998403162±0.000000005	18.998±0.001	2021
10	Ne	neon	20.1797±0.0006	20.180±0.001	1985
11	Na	sodium	22.98976928±0.00000002	22.990±0.001	2005
12	Mg	magnesium	[24.304, 24.307]	24.305±0.002	2011
13	Al	aluminium	26.9815384±0.0000003	26.982±0.001	2017
14	Si	silicon	[28.084, 28.086]	28.085±0.001	2009
15	P	phosphorus	30.973761998±0.000000005	30.974±0.001	2013
16	S	sulfur	[32.059, 32.076]	32.06±0.02	2009
17	Cl	chlorine	[35.446, 35.457]	35.45±0.01	2009
18	Ar	argon	[39.792, 39.963]	39.95±0.16	2017
19	K	potassium	39.0983±0.0001	39.098±0.001	1979
20	Ca	calcium	40.078±0.004	40.078±0.004	1983
21	Sc	scandium	44.955907±0.000004	44.956±0.001	2021
22	Ti	titanium	47.867±0.001	47.867±0.001	1993
23	V	vanadium	50.9415±0.0001	50.942±0.001	1977
24	Cr	chromium	51.9961±0.0006	51.996±0.001	1983
25	Mn	manganese	54.938043±0.000002	54.938±0.001	2017
26	Fe	iron	55.845±0.002	55.845±0.002	1993
27	Co	cobalt	58.933194±0.000003	58.933±0.001	2017
28	Ni	nickel	58.6934±0.0004	58.693±0.001	2007
29	Cu	copper	63.546±0.003	63.546±0.003	1969
30	Zn	zinc	65.38±0.02	65.38±0.02	2007
31	Ga	gallium	69.723±0.001	69.723±0.001	1987
32	Ge	germanium	72.630±0.008	72.630±0.008	2009
33	As	arsenic	74.921595±0.000006	74.922±0.001	2013
34	Se	selenium	78.971±0.008	78.971±0.008	2013
35	Br	bromine	[79.901, 79.907]	79.904±0.003	2011
36	Kr	krypton	83.798±0.002	83.798±0.002	2001
37	Rb	rubidium	85.4678±0.0003	85.468±0.001	1969
38	Sr	strontium	87.62±0.01	87.62±0.01	1969
39	Y	yttrium	88.905838±0.000002	88.906±0.001	2021
40	Zr	zirconium	91.224±0.002	91.224±0.002	1983
41	Nb	niobium	92.90637±0.00001	92.906±0.001	2017
42	Mo	molybdenum	95.95±0.01	95.95±0.01	2013
43	Tc	technetium	-
44	Ru	ruthenium	101.07±0.02	101.07±0.02	1983
45	Rh	rhodium	102.90549±0.00002	102.91±0.01	2017
46	Pd	palladium	106.42±0.01	106.42±0.01	1979
47	Ag	silver	107.8682±0.0002	107.87±0.01	1985
48	Cd	cadmium	112.414±0.004	112.41±0.01	2013
49	In	indium	114.818±0.001	114.82±0.01	2011
50	Sn	tin	118.710±0.007	118.71±0.01	1983
51	Sb	antimony	121.760±0.001	121.76±0.01	1993
52	Te	tellurium	127.60±0.03	127.60±0.03	1969
53	I	iodine	126.90447±0.00003	126.90±0.01	1985
54	Xe	xenon	131.293±0.006	131.29±0.01	1999
55	Cs	caesium	132.90545196±0.00000006	132.91±0.01	2013
56	Ba	barium	137.327±0.007	137.33±0.01	1985
57	La	lanthanum	138.90547±0.00007	138.91±0.01	2005
58	Ce	cerium	140.116±0.001	140.12±0.01	1995
59	Pr	praseodymium	140.90766±0.00001	140.91±0.01	2017
60	Nd	neodymium	144.242±0.003	144.24±0.01	2005
61	Pm	promethium
62	Sm	samarium	150.36±0.02	150.36±0.02	2005
63	Eu	europium	151.964±0.001	151.96±0.01	1995
64	Gd	gadolinium	157.25±0.03	157.25±0.03	1969
65	Tb	terbium	158.925354±0.000007	158.93±0.01	2021
66	Dy	dysprosium	162.500±0.001	162.50±0.01	2001
67	Ho	holmium	164.930329±0.000005	164.93±0.01	2021
68	Er	erbium	167.259±0.003	167.26±0.01	1999
69	Tm	thulium	168.934219±0.000005	168.93±0.01	2021
70	Yb	ytterbium	173.045±0.010	173.05±0.02	2015
71	Lu	lutetium	174.9668±0.0001	174.97±0.01	2007
72	Hf	hafnium	178.486±0.006	178.49±0.01	2019
73	Ta	tantalum	180.94788±0.00002	180.95±0.01	2005
74	W	tungsten	183.84±0.01	183.84±0.01	1991
75	Re	rhenium	186.207±0.001	186.21±0.01	1973
76	Os	osmium	190.23±0.03	190.23±0.03	1991
77	Ir	iridium	192.217±0.002	192.22±0.01	2017
78	Pt	platinum	195.084±0.009	195.08±0.02	2005
79	Au	gold	196.966570±0.000004	196.97±0.01	2017
80	Hg	mercury	200.592±0.003	200.59±0.01	2011
81	Tl	thallium	[204.382, 204.385]	204.38±0.01	2009
82	Pb	lead	[206.14, 207.94]	207.2±1.1	2020
83	Bi	bismuth	208.98040±0.00001	208.98±0.01	2005
84	Po	polonium	-
85	At	astatine	-
86	Rn	radon	-
87	Fr	francium	-
88	Ra	radium	-
89	Ac	actinium	-
90	Th	thorium	232.0377±0.0004	232.04±0.01	2013
91	Pa	protactinium	231.03588±0.00001	231.04±0.01	2017
92	U	uranium	238.02891±0.00003	238.03±0.01	1999
93	Np	neptunium	-
94	Pu	plutonium	-
95	Am	americium	-
96	Cm	curium	-
97	Bk	berkelium	-
98	Cf	californium	-
99	Es	einsteinium	-
100	Fm	fermium	-
101	Md	mendelevium	-
102	No	nobelium	-
103	Lr	lawrencium	-
104	Rf	rutherfordium	-
105	Db	dubnium	-
106	Sg	seaborgium	-
107	Bh	bohrium	-
108	Hs	hassium	-
109	Mt	meitnerium	-
110	Ds	darmstadtium	-
111	Rg	roentgenium	-
112	Cn	copernicium	-
113	Nh	nihonium	-
114	Fl	flerovium	-
115	Mc	moscovium	-
116	Lv	livermorium	-
117	Ts	tennessine	-
118	Og	oganesson	-

CIAAW may publish changes to atomic weights (including its precision and derived values). Since 1947, any update this is done in odd years nominally; the actual date of publication may be some time later.

• 2009 {{CIAAW2009}} (introducing interval notation; Ge):

"Atomic weights of the elements 2009 (IUPAC Technical Report)". Pure Appl. Chem. 83 (2): 359–396. 12 December 2010. doi:10.1351/PAC-REP-10-09-14.

• 2011 {{CIAAW2011}} (interval for Br, Mg):

"Atomic weights of the elements 2011 (IUPAC Technical Report)". Pure Appl. Chem. 85 (5): 1047–1078. 29 April 2013. doi:10.1351/PAC-REP-13-03-02.

• 2013 {{CIAAW2013}} (all elements listed):

Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305.

• 2015 {{CIAAW2015}} (ytterbium changed):

"Standard Atomic Weight of Ytterbium Revised". Chemistry International. 37 (5–6): 26. October 2015. doi:10.1515/ci-2015-0512. eISSN 0193-6484. ISSN 0193-6484.

• 2017 {{CIAAW2017}} (14 values changed):

"Standard atomic weights of 14 chemical elements revised". CIAAW. 2018-06-05.

• 2019 (hafnium value changed): Meija, Juris; et al. (2019-12-09). "Standard atomic weight of hafnium revised". CIAAW. Retrieved 2020-02-25.
• 2020* (lead value changed): Zhu, Xiang-Kun; Benefield, Jacqueline; Coplen, Tyler B.; Gao, Zhaofu; Holden, Norman E. (1 October 2020). "Variation of lead isotopic composition and atomic weight in terrestrial materials (IUPAC Technical Report)". doi:10.1515/pac-2018-0916.

* "2020" is an inconsistent year for change publication: CIAAW maintains that only odd years, changes are publicised.

• 2021 {{CIAAW2021}} (all elements listed); (4 values changed; introduced new symbol; merge "conventional" into "abridged" columns; change uncertainty notation (use "±")

Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.

Uncertainty handling

About notation and handling of the uncertainty in the values, including those in [ ] range values:

• Possolo, Antonio; van der Veen, Adriaan M.H.; Meija, Juris; et al. (4 Jan 2018). "Interpreting and propagating the uncertainty of the standard atomic weights (IUPAC Technical Report)". doi:10.1515/pac-2016-0402. Retrieved 20 Oct 2020.
• {{CIAAW2021}}: changing notation (i.e., interpretation, not the value) from 123.45(2) into 123.45±0.02

See also: {{Isotopes table/references}}