List of elements by atomic number

A table of chemical elements ordered by atomic number and color coded according to type of element. Each element's name, element symbol, group and period, atomic mass (or most stable isotope), density, melting point, boiling point and discoverer are given.

No.	Name	Symbol	Period, Group	Mass (g/mol)	Density (g/cm³) at 20°C	Melting p. (°C)	Boiling p. (°C)	Year of discovery	Discoverer
1	Hydrogen	H	1, 1	1.00794(7)	0.084 g/l	-259.1	-252.9	1766	Cavendish
2	Helium	He	1, 18	4.002602(2)	0.17 g/l	-272.2 (at 2.5 MPa)	-268.9	1895	Ramsay and Cleve
3	Lithium	Li	2, 1	6.941(2)	0.53	180.5	1317	1817	Arfwedson
4	Beryllium	Be	2, 2	9.012182(3)	1.85	1278	2970	1797	Vauquelin
5	Boron	B	2, 13	10.811(7)	2.46	2300	2550	1808	Davy and Gay-Lussac
6	Carbon	C	2, 14	12.0107(8)	3.51	3550	4827	prehistoric	unknown
7	Nitrogen	N	2, 15	14.0067(2)	1.17 g/l	-209.9	-195.8	1772	Rutherford
8	Oxygen	O	2, 16	15.9994(3)	1.33 g/l	-218.4	-182.9	1774	Priestly and Scheele
9	Fluorine	F	2, 17	18.9984032(5)	1.58 g/l	-219.6	-188.1	1886	Moissan
10	Neon	Ne	2, 18	20.1797(6)	0.84 g/l	-248.7	-246.1	1898	Ramsay and Travers
11	Sodium	Na	3, 1	22.98976928(2)	0.97	97.8	892	1807	Davy
12	Magnesium	Mg	3, 2	24.3050(6)	1.74	648.8	1107	1755	Black
13	Aluminium	Al	3, 13	26.9815386(8)	2.70	660.5	2467	1825	Oersted
14	Silicon	Si	3, 14	28.0855(3)	2.33	1410	2355	1824	Berzelius
15	Phosphorus	P	3, 15	30.973762(2)	1.82	44 (P4)	280 (P4)	1669	Brand
16	Sulfur	S	3, 16	32.065(5)	2.06	113	444.7	prehistoric	unknown
17	Chlorine	Cl	3, 17	35.453(2)	2.95 g/l	-34.6	-101	1774	Scheele
18	Argon	Ar	3, 18	39.948(1)	1.66 g/l	-189.4	-185.9	1894	Ramsay and Rayleigh
19	Potassium	K	4, 1	39.0983(1)	0.86	63.7	774	1807	Davy
20	Calcium	Ca	4, 2	40.078(4)	1.54	839	1487	1808	Davy
21	Scandium	Sc	4, 3	44.955912(6)	2.99	1539	2832	1879	Nilson
22	Titanium	Ti	4, 4	47.867(1)	4.51	1660	3260	1791	Gregor and Klaproth
23	Vanadium	V	4, 5	50.9415(1)	6.09	1890	3380	1801	del Río
24	Chromium	Cr	4, 6	51.9961(6)	7.14	1857	2482	1797	Vauquelin
25	Manganese	Mn	4, 7	54.938045(5)	7.44	1244	2097	1774	Gahn
26	Iron	Fe	4, 8	55.845(2)	7.87	1535	2750	prehistoric	unknown
27	Cobalt	Co	4, 9	58.933195(5)	8.89	1495	2870	1735	Brandt
28	Nickel	Ni	4, 10	58.6934(2)	8.91	1453	2732	1751	Cronstedt
29	Copper	Cu	4, 11	63.546(3)	8.92	1083.5	2595	prehistoric	unknown
30	Zinc	Zn	4, 12	65.409(4)	7.14	419.6	907	prehistoric	unknown
31	Gallium	Ga	4, 13	69.723(1)	5.91	29.8	2403	1875	Lecoq de Boisbaudran
32	Germanium	Ge	4, 14	72.64(1)	5.32	937.4	2830	1886	Winkler
33	Arsenic	As	4, 15	74.92160(2)	5.72	613	613 (subl.)	ca. 1250	Albertus Magnus
34	Selenium	Se	4, 16	78.96(3)	4.82	217	685	1817	Berzelius
35	Bromine	Br	4, 17	79.904(1)	3.14	-7.3	58.8	1826	Balard
36	Krypton	Kr	4, 18	83.798(2)	3.48 g/l	-156.6	-152.3	1898	Ramsay and Travers
37	Rubidium	Rb	5, 1	85.4678(3)	1.53	39	688	1861	Bunsen and Kirchhoff
38	Strontium	Sr	5, 2	87.62(1)	2.63	769	1384	1790	Crawford
39	Yttrium	Y	5, 3	88.90585(2)	4.47	1523	3337	1794	Gadolin
40	Zirconium	Zr	5, 4	91.224(2)	6.51	1852	4377	1789	Klaproth
41	Niobium	Nb	5, 5	92.906 38(2)	8.58	2468	4927	1801	Hatchett
42	Molybdenum	Mo	5, 6	95.94(2)	10.28	2617	5560	1778	Scheele
43	Technetium	Tc	5, 7	^*	11.49	2172	5030	1937	Perrier and Segrè
44	Ruthenium	Ru	5, 8	101.07(2)	12.45	2310	3900	1844	Klaus
45	Rhodium	Rh	5, 9	102.90550(2)	12.41	1966	3727	1803	Wollaston
46	Palladium	Pd	5, 10	106.42(1)	12.02	1552	3140	1803	Wollaston
47	Silver	Ag	5, 11	107.8682(2)	10.49	961.9	2212	prehistoric	unknown
48	Cadmium	Cd	5, 12	112.411(8)	8.64	321	765	1817	Strohmeyer and Hermann
49	Indium	In	5, 13	114.818(3)	7.31	156.2	2080	1863	Reich and Richter
50	Tin	Sn	5, 14	118.710(7)	7.29	232	2270	prehistoric	unknown
51	Antimony	Sb	5, 15	121.760(1)	6.69	630.7	1750	prehistoric	unknown
52	Tellurium	Te	5, 16	127.60(3)	6.25	449.6	990	1782	von Reichenstein
53	Iodine	I	5, 17	126.90447(3)	4.94	113.5	184.4	1811	Courtois
54	Xenon	Xe	5, 18	131.293(6)	4.49 g/l	-111.9	-107	1898	Ramsay and Travers
55	Caesium	Cs	6, 1	132.9054519(2)	1.90	28.4	690	1860	Kirchhoff and Bunsen
56	Barium	Ba	6, 2	137.327(7)	3.65	725	1640	1808	Davy
57	Lanthanum	La	6	138.90547(7)	6.16	920	3454	1839	Mosander
58	Cerium	Ce	6	140.116(1)	6.77	798	3257	1803	von Hisinger and Berzelius
59	Praseodymium	Pr	6	140.90765(2)	6.48	931	3212	1895	von Welsbach
60	Neodymium	Nd	6	144.242(3)	7.00	1010	3127	1895	von Welsbach
61	Promethium	Pm	6	^*	7.22	1080	2730	1945	Marinsky and Glendenin
62	Samarium	Sm	6	150.36(2)	7.54	1072	1778	1879	Lecoq de Boisbaudran
63	Europium	Eu	6	151.964(1)	5.25	822	1597	1901	Demarçay
64	Gadolinium	Gd	6	157.25(3)	7.89	1311	3233	1880	de Marignac
65	Terbium	Tb	6	158.92535(2)	8.25	1360	3041	1843	Mosander
66	Dysprosium	Dy	6	162.500(1)	8.56	1409	2335	1886	Lecoq de Boisbaudran
67	Holmium	Ho	6	164.93032(2)	8.78	1470	2720	1878	Soret
68	Erbium	Er	6	167.259(3)	9.05	1522	2510	1842	Mosander
69	Thulium	Tm	6	168.93421(2)	9.32	1545	1727	1879	Cleve
70	Ytterbium	Yb	6	173.04(3)	6.97	824	1193	1878	de Marignac
71	Lutetium	Lu	6, 3	174.967(1)	9.84	1656	3315	1907	Urbain
72	Hafnium	Hf	6, 4	178.49(2)	13.31	2150	5400	1923	Coster and de Hevesy
73	Tantalum	Ta	6, 5	180.9479(1)	16.68	2996	5425	1802	Ekeberg
74	Tungsten	W	6, 6	183.84(1)	19.26	3407	5927	1783	Elhuyar
75	Rhenium	Re	6, 7	186.207(1)	21.03	3180	5627	1925	Noddack, Tacke and Berg
76	Osmium	Os	6, 8	190.23(3)	22.61	3045	5027	1803	Tennant
77	Iridium	Ir	6, 9	192.217(3)	22.65	2410	4130	1803	Tennant
78	Platinum	Pt	6, 10	195.084(9)	21.45	1772	3827	1557	Scaliger
79	Gold	Au	6, 11	196.966569(4)	19.32	1064.4	2940	prehistoric	unknown
80	Mercury	Hg	6, 12	200.59(2)	13.55	-38.9	356.6	prehistoric	unknown
81	Thallium	Tl	6, 13	204.3833(2)	11.85	303.6	1457	1861	Crookes
82	Lead	Pb	6, 14	207.2(1)	11.34	327.5	1740	prehistoric	unknown
83	Bismuth	Bi	6, 15	208.98040(1)	9.80	271.4	1560	1540	Geoffroy
84	Polonium	Po	6, 16	^*	9.20	254	962	1898	Marie and Pierre Curie
85	Astatine	At	6, 17	^*		302	337	1940	Corson and MacKenzie
86	Radon	Rn	6, 18	^*	9.23 g/l	-71	-61.8	1900	Dorn
87	Francium	Fr	7, 1	^*		27	677	1939	Perey
88	Radium	Ra	7, 2	^*	5.50	700	1140	1898	Marie and Pierre Curie
89	Actinium	Ac	7	^*	10.07	1047	3197	1899	Debierne
90	Thorium	Th	7	232.03806(2)	11.72	1750	4787	1829	Berzelius
91	Protactinium	Pa	7	231.03588(2)	15.37	1554	4030	1917	Soddy, Cranston and Hahn
92	Uranium	U	7	238.02891(3)	18.97	1132.4	3818	1789	Klaproth
93	Neptunium	Np	7	^*	20.48	640	3902	1940	McMillan and Abelson
94	Plutonium	Pu	7	^*	19.74	641	3327	1940	Seaborg
95	Americium	Am	7	^*	13.67	994	2607	1944	Seaborg
96	Curium	Cm	7	^*	13.51	1340		1944	Seaborg
97	Berkelium	Bk	7	^*	13.25	986		1949	Seaborg
98	Californium	Cf	7	^*	15.1	900		1950	Seaborg
99	Einsteinium	Es	7	^*		860		1952	Seaborg
100	Fermium	Fm	7	^*				1952	Seaborg
101	Mendelevium	Md	7	^*				1955	Seaborg
102	Nobelium	No	7	^*				1958	Seaborg
103	Lawrencium	Lr	7, 3	^*				1961	Ghiorso
104	Rutherfordium	Rf	7, 4	^*				1964/69	Flerov
105	Dubnium	Db	7, 5	^*				1967/70	Flerov
106	Seaborgium	Sg	7, 6	^*				1974	Flerov
107	Bohrium	Bh	7, 7	^*				1976	Oganessian
108	Hassium	Hs	7, 8	^*				1984	GSI (*)
109	Meitnerium	Mt	7, 9	^*				1982	GSI
110	Darmstadtium	Ds	7, 10	^*				1994	GSI
111	Roentgenium	Rg	7, 11	^*				1994	GSI
112	Ununbium	Uub	7, 12	^*				1996	GSI
113	Ununtrium	Uut	7, 13	^*				2004	JINR (), LLNL ()
114	Ununquadium	Uuq	7, 14	^*				1999	JINR
115	Ununpentium	Uup	7, 15	^*				2004	JINR, LLNL
116	Ununhexium	Uuh	7, 16	^*				1999	LBNL (*)
117	Ununseptium	Uus	7, 17					undiscovered
118	Ununoctium	Uuo	7, 18					undiscovered

Acronyms

GSI, Gesellschaft für Schwerionenforschung (Society for Heavy Ion Research), Wixhausen, Darmstadt, Germany
JINR, Joint Institute for Nuclear Research (Объединённый институт ядерных исследований), Dubna, Moscow Oblast, Russia
LLNL, Lawrence Livermore National Laboratory, Livermore, California, USA
LBNL, Lawrence Berkeley National Laboratory, Berkeley, California, USA

Notes

The element does not have any stable nuclides, and a value in brackets, e.g. ^*, indicates the mass number of the longest-lived isotope of the element or characteristic isotopic composition.
The isotopic composition of this element varies in some geological specimens, and the variation may exceed the uncertainty stated in the table.
The isotopic composition of the element can vary in commercial materials, which can cause the atomic weight to deviate significantly from the given value.
The isotopic composition varies in terrestrial material such that a more precise atomic weight can not be given.
The atomic weight of commercial Lithium can vary between 6.939 and 6.996—analysis of the specific material is necessary to find a more accurate value.

References

Atomic Weights of the Elements 2001, Pure Appl. Chem. 75(8), 1107-1122, 2003. Retrieved June 30, 2005. Atomic weights of elements with atomic numbers from 1-109 taken from this source.
IUPAC Standard Atomic Weights Revised (2005).
WebElements Periodic Table. Retrieved June 30, 2005. Atomic weights of elements with atomic numbers 110-116 taken from this source.

Chemical elements | Chemistry

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Acronyms

Notes

References