The elements of the periodic table sorted by atomic mass

click on any element's name for further information on chemical properties, environmental data or health effects.

As early as 1850, chemists used a unit of atomic weight based on saying the atomic weight of oxygen was 16. Oxygen was chosen because it forms chemical compounds with many other elements, simplifying determination of their atomic weights. Sixteen was chosen because it was the lowest whole number that could be assigned to oxygen and still have. Start studying First 50 Elements of the Periodic Table- Atomic Mass. Learn vocabulary, terms, and more with flashcards, games, and other study tools. This is a list of the 118 chemical elements which have been identified as of 2021. A chemical element, often simply called an element, is a species of atoms which all have the same number of protons in their atomic nuclei (i.e., the same atomic number, or Z). Each element is uniquely defined by its atomic number. Atomic mass: The mass of an atom is primarily determined by the number of protons and neutrons in its nucleus. Atomic mass is measured in Atomic Mass Units (amu) which are scaled relative to carbon, 12 C, that is taken as a standard element with an atomic mass of 12. This isotope of carbon.

This list contains the 118 elements of chemistry.

The chemical elements of the periodic chart sorted by:	Atomic Mass	Name chemical element	Symbol	Atomic number
- Name alphabetically	1.0079	Hydrogen	H	1
- Atomic number	4.0026	Helium	He	2
- Symbol	6.941	Lithium	Li	3
- Atomic Mass	9.0122	Beryllium	Be	4
- Electronegativity	10.811	Boron	B	5
- Density	12.0107	Carbon	C	6
- Melting point	14.0067	Nitrogen	N	7
- Boiling point	15.9994	Oxygen	O	8
- Vanderwaals radius	18.9984	Fluorine	F	9
- Year of discovery	20.1797	Neon	Ne	10
- Inventor surname	22.9897	Sodium	Na	11
- Elements in earthcrust	24.305	Magnesium	Mg	12
- Elements in human body	26.9815	Aluminum	Al	13
- Covalenz radius	28.0855	Silicon	Si	14
- Ionization energy	30.9738	Phosphorus	P	15
For chemistry students and teachers: The tabular chart on the right is arranged by Atomic mass (weight). The lightest chemical element is Hydrogen and the heaviest is Hassium. The unity for atomic mass is gram per mol. Please note that the elements do not show their natural relation towards each other as in the Periodic system. There you can find the metals, semi-conductor(s), non-metal(s), inert noble gas(ses), Halogens, Lanthanoides, Actinoids (rare earth elements) and transition metals.	32.065	Sulfur	S	16
	35.453	Chlorine	Cl	17
	39.0983	Potassium	K	19
	39.948	Argon	Ar	18
	40.078	Calcium	Ca	20
	44.9559	Scandium	Sc	21
	47.867	Titanium	Ti	22
	50.9415	Vanadium	V	23
	51.9961	Chromium	Cr	24
	54.938	Manganese	Mn	25
	55.845	Iron	Fe	26
	58.6934	Nickel	Ni	28
	58.9332	Cobalt	Co	27
	63.546	Copper	Cu	29
	65.39	Zinc	Zn	30
	69.723	Gallium	Ga	31
	72.64	Germanium	Ge	32
	74.9216	Arsenic	As	33
	78.96	Selenium	Se	34
79.904	Bromine	Br	35
83.8	Krypton	Kr	36
85.4678	Rubidium	Rb	37
87.62	Strontium	Sr	38
88.9059	Yttrium	Y	39
91.224	Zirconium	Zr	40
92.9064	Niobium	Nb	41
95.94	Molybdenum	Mo	42
98	Technetium	Tc	43
101.07	Ruthenium	Ru	44
102.9055	Rhodium	Rh	45
106.42	Palladium	Pd	46
107.8682	Silver	Ag	47
112.411	Cadmium	Cd	48
114.818	Indium	In	49
118.71	Tin	Sn	50
121.76	Antimony	Sb	51
126.9045	Iodine	I	53
127.6	Tellurium	Te	52
131.293	Xenon	Xe	54
132.9055	Cesium	Cs	55
137.327	Barium	Ba	56
138.9055	Lanthanum	La	57
140.116	Cerium	Ce	58
140.9077	Praseodymium	Pr	59
144.24	Neodymium	Nd	60
145	Promethium	Pm	61
150.36	Samarium	Sm	62
151.964	Europium	Eu	63
157.25	Gadolinium	Gd	64
158.9253	Terbium	Tb	65
162.5	Dysprosium	Dy	66
164.9303	Holmium	Ho	67
167.259	Erbium	Er	68
168.9342	Thulium	Tm	69
173.04	Ytterbium	Yb	70
174.967	Lutetium	Lu	71
178.49	Hafnium	Hf	72
180.9479	Tantalum	Ta	73
183.84	Tungsten	W	74
186.207	Rhenium	Re	75
190.23	Osmium	Os	76
192.217	Iridium	Ir	77
195.078	Platinum	Pt	78
196.9665	Gold	Au	79
200.59	Mercury	Hg	80
204.3833	Thallium	Tl	81
207.2	Lead	Pb	82
208.9804	Bismuth	Bi	83
209	Polonium	Po	84
210	Astatine	At	85
222	Radon	Rn	86
223	Francium	Fr	87
226	Radium	Ra	88
227	Actinium	Ac	89
231.0359	Protactinium	Pa	91
232.0381	Thorium	Th	90
237	Neptunium	Np	93
238.0289	Uranium	U	92
243	Americium	Am	95
244	Plutonium	Pu	94
247	Curium	Cm	96
247	Berkelium	Bk	97
251	Californium	Cf	98
252	Einsteinium	Es	99
257	Fermium	Fm	100
258	Mendelevium	Md	101
259	Nobelium	No	102
261	Rutherfordium	Rf	104
262	Lawrencium	Lr	103
262	Dubnium	Db	105
264	Bohrium	Bh	107
266	Seaborgium	Sg	106
268	Meitnerium	Mt	109
272	Roentgenium	Rg	111
277	Hassium	Hs	108
Darmstadtium	Ds	110
Copernicium	Cn	112
Nihonium	Nh	113
Flerovium	Fl	114
Moscovium	Mc	115
Livermorium	Lv	116
Tennessine	Ts	117
Oganesson	Og	118

Click here: for a schematic overview of the periodic table of elements in chart form

Atomic Mass Of First 50 Elements Approximately

Do you need to know the weight of some molecules? Try our Molecular Weight Calculator!

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Atomic Mass Of First 50 Elements Discovered

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Click a column header, such as Name, to sort the table by that item.
SEENotes at the bottom of the Table.

No.		Atomic weight	Name	Sym.	M.P. (°C)	B.P. (°C)	Density* (g/cm3)	Earth crust (%)*	Discovery (Year)	Group*	Electron configuration	Ionization energy (eV)
1	1.008	Hydrogen	H	-259	-253	0.09	0.14	1776	1	1s1	13.60
2	4.003	Helium	He	-272	-269	0.18	1895	18	1s2	24.59
3	6.941	Lithium	Li	180	1,347	0.53	1817	1	[He] 2s1	5.39
4	9.012	Beryllium	Be	1,278	2,970	1.85	1797	2	[He] 2s2	9.32
5	10.811	Boron	B	2,300	2,550	2.34	1808	13	[He] 2s2 2p1	8.30
6	12.011	Carbon	C	3,500	4,827	2.26	0.09	ancient	14	[He] 2s2 2p2	11.26
7	14.007	Nitrogen	N	-210	-196	1.25	1772	15	[He] 2s2 2p3	14.53
8	15.999	Oxygen	O	-218	-183	1.43	46.71	1774	16	[He] 2s2 2p4	13.62
9	18.998	Fluorine	F	-220	-188	1.70	0.03	1886	17	[He] 2s2 2p5	17.42
10	20.180	Neon	Ne	-249	-246	0.90	1898	18	[He] 2s2 2p6	21.56
11	22.990	Sodium	Na	98	883	0.97	2.75	1807	1	[Ne] 3s1	5.14
12	24.305	Magnesium	Mg	639	1,090	1.74	2.08	1755	2	[Ne] 3s2	7.65
13	26.982	Aluminum	Al	660	2,467	2.70	8.07	1825	13	[Ne] 3s2 3p1	5.99
14	28.086	Silicon	Si	1,410	2,355	2.33	27.69	1824	14	[Ne] 3s2 3p2	8.15
15	30.974	Phosphorus	P	44	280	1.82	0.13	1669	15	[Ne] 3s2 3p3	10.49
16	32.065	Sulfur	S	113	445	2.07	0.05	ancient	16	[Ne] 3s2 3p4	10.36
17	35.453	Chlorine	Cl	-101	-35	3.21	0.05	1774	17	[Ne] 3s2 3p5	12.97
18	39.948	Argon	Ar	-189	-186	1.78	1894	18	[Ne] 3s2 3p6	15.76
19	39.098	Potassium	K	64	774	0.86	2.58	1807	1	[Ar] 4s1	4.34
20	40.078	Calcium	Ca	839	1,484	1.55	3.65	1808	2	[Ar] 4s2	6.11
21	44.956	Scandium	Sc	1,539	2,832	2.99	1879	3	[Ar] 3d1 4s2	6.56
22	47.867	Titanium	Ti	1,660	3,287	4.54	0.62	1791	4	[Ar] 3d2 4s2	6.83
23	50.942	Vanadium	V	1,890	3,380	6.11	1830	5	[Ar] 3d3 4s2	6.75
24	51.996	Chromium	Cr	1,857	2,672	7.19	0.04	1797	6	[Ar] 3d5 4s1	6.77
25	54.938	Manganese	Mn	1,245	1,962	7.43	0.09	1774	7	[Ar] 3d5 4s2	7.43
26	55.845	Iron	Fe	1,535	2,750	7.87	5.05	ancient	8	[Ar] 3d6 4s2	7.90
27	58.933	Cobalt	Co	1,495	2,870	8.90	1735	9	[Ar] 3d7 4s2	7.88
28	58.693	Nickel	Ni	1,453	2,732	8.90	0.02	1751	10	[Ar] 3d8 4s2	7.64
29	63.546	Copper	Cu	1,083	2,567	8.96	ancient	11	[Ar] 3d10 4s1	7.73
30	65.390	Zinc	Zn	420	907	7.13	ancient	12	[Ar] 3d10 4s2	9.39
31	69.723	Gallium	Ga	30	2,403	5.91	1875	13	[Ar] 3d10 4s2 4p1	6.00
32	72.640	Germanium	Ge	937	2,830	5.32	1886	14	[Ar] 3d10 4s2 4p2	7.90
33	74.922	Arsenic	As	81	613	5.72	ancient	15	[Ar] 3d10 4s2 4p3	9.79
34	78.960	Selenium	Se	217	685	4.79	1817	16	[Ar] 3d10 4s2 4p4	9.75
35	79.904	Bromine	Br	-7	59	3.12	1826	17	[Ar] 3d10 4s2 4p5	11.81
36	83.800	Krypton	Kr	-157	-153	3.75	1898	18	[Ar] 3d10 4s2 4p6	14.00
37	85.468	Rubidium	Rb	39	688	1.63	1861	1	[Kr] 5s1	4.18
38	87.620	Strontium	Sr	769	1,384	2.54	1790	2	[Kr] 5s2	5.69
39	88.906	Yttrium	Y	1,523	3,337	4.47	1794	3	[Kr] 4d1 5s2	6.22
40	91.224	Zirconium	Zr	1,852	4,377	6.51	0.03	1789	4	[Kr] 4d2 5s2	6.63
41	92.906	Niobium	Nb	2,468	4,927	8.57	1801	5	[Kr] 4d4 5s1	6.76
42	95.940	Molybdenum	Mo	2,617	4,612	10.22	1781	6	[Kr] 4d5 5s1	7.09
43	*	98.000	Technetium	Tc	2,200	4,877	11.50	1937	7	[Kr] 4d5 5s2	7.28
44	101.070	Ruthenium	Ru	2,250	3,900	12.37	1844	8	[Kr] 4d7 5s1	7.36
45	102.906	Rhodium	Rh	1,966	3,727	12.41	1803	9	[Kr] 4d8 5s1	7.46
46	106.420	Palladium	Pd	1,552	2,927	12.02	1803	10	[Kr] 4d10	8.34
47	107.868	Silver	Ag	962	2,212	10.50	ancient	11	[Kr] 4d10 5s1	7.58
48	112.411	Cadmium	Cd	321	765	8.65	1817	12	[Kr] 4d10 5s2	8.99
49	114.818	Indium	In	157	2,000	7.31	1863	13	[Kr] 4d10 5s2 5p1	5.79
50	118.710	Tin	Sn	232	2,270	7.31	ancient	14	[Kr] 4d10 5s2 5p2	7.34
51	121.760	Antimony	Sb	630	1,750	6.68	ancient	15	[Kr] 4d10 5s2 5p3	8.61
52	127.600	Tellurium	Te	449	990	6.24	1783	16	[Kr] 4d10 5s2 5p4	9.01
53	126.905	Iodine	I	114	184	4.93	1811	17	[Kr] 4d10 5s2 5p5	10.45
54	131.293	Xenon	Xe	-112	-108	5.90	1898	18	[Kr] 4d10 5s2 5p6	12.13
55	132.906	Cesium	Cs	29	678	1.87	1860	1	[Xe] 6s1	3.89
56	137.327	Barium	Ba	725	1,140	3.59	0.05	1808	2	[Xe] 6s2	5.21
57	138.906	Lanthanum	La	920	3,469	6.15	1839	3	[Xe] 5d1 6s2	5.58
58	140.116	Cerium	Ce	795	3,257	6.77	1803	101	[Xe] 4f1 5d1 6s2	5.54
59	140.908	Praseodymium	Pr	935	3,127	6.77	1885	101	[Xe] 4f3 6s2	5.47
60	144.240	Neodymium	Nd	1,010	3,127	7.01	1885	101	[Xe] 4f4 6s2	5.53
61	*	145.000	Promethium	Pm	1,100	3,000	7.30	1945	101	[Xe] 4f5 6s2	5.58
62	150.360	Samarium	Sm	1,072	1,900	7.52	1879	101	[Xe] 4f6 6s2	5.64
63	151.964	Europium	Eu	822	1,597	5.24	1901	101	[Xe] 4f7 6s2	5.67
64	157.250	Gadolinium	Gd	1,311	3,233	7.90	1880	101	[Xe] 4f7 5d1 6s2	6.15
65	158.925	Terbium	Tb	1,360	3,041	8.23	1843	101	[Xe] 4f9 6s2	5.86
66	162.500	Dysprosium	Dy	1,412	2,562	8.55	1886	101	[Xe] 4f10 6s2	5.94
67	164.930	Holmium	Ho	1,470	2,720	8.80	1867	101	[Xe] 4f11 6s2	6.02
68	167.259	Erbium	Er	1,522	2,510	9.07	1842	101	[Xe] 4f12 6s2	6.11
69	168.934	Thulium	Tm	1,545	1,727	9.32	1879	101	[Xe] 4f13 6s2	6.18
70	173.040	Ytterbium	Yb	824	1,466	6.90	1878	101	[Xe] 4f14 6s2	6.25
71	174.967	Lutetium	Lu	1,656	3,315	9.84	1907	101	[Xe] 4f14 5d1 6s2	5.43
72	178.490	Hafnium	Hf	2,150	5,400	13.31	1923	4	[Xe] 4f14 5d2 6s2	6.83
73	180.948	Tantalum	Ta	2,996	5,425	16.65	1802	5	[Xe] 4f14 5d3 6s2	7.55
74	183.840	Tungsten	W	3,410	5,660	19.35	1783	6	[Xe] 4f14 5d4 6s2	7.86
75	186.207	Rhenium	Re	3,180	5,627	21.04	1925	7	[Xe] 4f14 5d5 6s2	7.83
76	190.230	Osmium	Os	3,045	5,027	22.60	1803	8	[Xe] 4f14 5d6 6s2	8.44
77	192.217	Iridium	Ir	2,410	4,527	22.40	1803	9	[Xe] 4f14 5d7 6s2	8.97
78	195.078	Platinum	Pt	1,772	3,827	21.45	1735	10	[Xe] 4f14 5d9 6s1	8.96
79	196.967	Gold	Au	1,064	2,807	19.32	ancient	11	[Xe] 4f14 5d10 6s1	9.23
80	200.590	Mercury	Hg	-39	357	13.55	ancient	12	[Xe] 4f14 5d10 6s2	10.44
81	204.383	Thallium	Tl	303	1,457	11.85	1861	13	[Xe] 4f14 5d10 6s2 6p1	6.11
82	207.200	Lead	Pb	327	1,740	11.35	ancient	14	[Xe] 4f14 5d10 6s2 6p2	7.42
83	208.980	Bismuth	Bi	271	1,560	9.75	ancient	15	[Xe] 4f14 5d10 6s2 6p3	7.29
84	*	209.000	Polonium	Po	254	962	9.30	1898	16	[Xe] 4f14 5d10 6s2 6p4	8.42
85	*	210.000	Astatine	At	302	337	0.00	1940	17	[Xe] 4f14 5d10 6s2 6p5	9.30
86	*	222.000	Radon	Rn	-71	-62	9.73	1900	18	[Xe] 4f14 5d10 6s2 6p6	10.75
87	*	223.000	Francium	Fr	27	677	0.00	1939	1	[Rn] 7s1	4.07
88	*	226.000	Radium	Ra	700	1,737	5.50	1898	2	[Rn] 7s2	5.28
89	*	227.000	Actinium	Ac	1,050	3,200	10.07	1899	3	[Rn] 6d1 7s2	5.17
90	232.038	Thorium	Th	1,750	4,790	11.72	1829	102	[Rn] 6d2 7s2	6.31
91	231.036	Protactinium	Pa	1,568	0	15.40	1913	102	[Rn] 5f2 6d1 7s2	5.89
92	238.029	Uranium	U	1,132	3,818	18.95	1789	102	[Rn] 5f3 6d1 7s2	6.19
93	*	237.000	Neptunium	Np	640	3,902	20.20	1940	102	[Rn] 5f4 6d1 7s2	6.27
94	*	244.000	Plutonium	Pu	640	3,235	19.84	1940	102	[Rn] 5f6 7s2	6.03
95	*	243.000	Americium	Am	994	2,607	13.67	1944	102	[Rn] 5f7 7s2	5.97
96	*	247.000	Curium	Cm	1,340	0	13.50	1944	102	5.99
97	*	247.000	Berkelium	Bk	986	0	14.78	1949	102	6.20
98	*	251.000	Californium	Cf	900	0	15.10	1950	102	6.28
99	*	252.000	Einsteinium	Es	860	0	0.00	1952	102	6.42
100	*	257.000	Fermium	Fm	1,527	0	0.00	1952	102	6.50
101	*	258.000	Mendelevium	Md	0	0	0.00	1955	102	6.58
102	*	259.000	Nobelium	No	827	0	0.00	1958	102	6.65
103	*	262.000	Lawrencium	Lr	1,627	0	0.00	1961	102	4.90
104	*	261.000	Rutherfordium	Rf	0	0	0.00	1964	4	0.00
105	*	262.000	Dubnium	Db	0	0	0.00	1967	5	0.00
106	*	266.000	Seaborgium	Sg	0	0	0.00	1974	6	0.00
107	*	264.000	Bohrium	Bh	0	0	0.00	1981	7	0.00
108	*	277.000	Hassium	Hs	0	0	0.00	1984	8	0.00
109	*	268.000	Meitnerium	Mt	0	0	0.00	1982	9	0.00
No.		Atomic weight	Name	Sym.	M.P. (°C)	B.P. (°C)	Density* (g/cm3)	Earth crust (%)*	Discovery (Year)	Group*	Electron configuration	Ionization energy (eV)

Notes:
• Density of elements with boiling points below 0°C is given in g/l. In a sorted list, these elements are shown before other elements that have boiling points >0°C.
• Earth crust composition average values are from a report by F. W. Clarke and H. S. Washington, 1924. Elemental composition of crustal rocks differ between different localities (see article).
• Group: There are only 18 groups in the periodic table that constitute the columns of the table. Lanthanoids and Actinoids are numbered as 101 and 102 to separate them in sorting by group.
• The elements marked with an asterisk (in the 2nd column) have no stable nuclides. For these elements the weight value shown represents the mass number of the longest-lived isotope of the element.

Abbreviations and Definitions:

No. - Atomic Number; M.P. - melting point; B.P. - boiling point

Atomic number: The number of protons in an atom. Each element is uniquely defined by its atomic number.

Atomic mass: The mass of an atom is primarily determined by the number of protons and neutrons in its nucleus. Atomic mass is measured in Atomic Mass Units (amu) which are scaled relative to carbon, ¹²C, that is taken as a standard element with an atomic mass of 12. This isotope of carbon has 6 protons and 6 neutrons. Thus, each proton and neutron has a mass of about 1 amu.

Isotope: Atoms of the same element with the same atomic number, but different number of neutrons. Isotope of an element is defined by the sum of the number of protons and neutrons in its nucleus. Elements have more than one isotope with varying numbers of neutrons. For example, there are two common isotopes of carbon, ¹²C and ¹³C which have 6 and 7 neutrons respectively. The abundances of different isotopes of elements vary in nature depending on the source of materials. For relative abundances of isotopes in nature see reference on Atomic Weights and Isotopic Compositions.

Atomic weight: Atomic weight values represent weighted average of the masses of all naturally occurring isotopes of an element. The values shown here are based on the IUPAC Commission determinations (Pure Appl. Chem. 73:667-683, 2001). The elements marked with an asterisk have no stable nuclides. For these elements the weight value shown represents the mass number of the longest-lived isotope of the element.

Electron configuration: See next page for explanation of electron configuration of atoms.

List Of Atomic Elements — VAMDC Standards Documentation

Ionization energy (IE): The energy required to remove the outermost electron from an atom or a positive ion in its ground level. The table lists only the first IE in eV units. To convert to kJ/mol multiply by 96.4869. Reference: NIST Reference Table on Ground states and ionization energies for the neutral atoms. IE decreases going down a column of the periodic table, and increases from left to right in a row. Thus, alkali metals have the lowest IE in a period and Rare gases have the highest.

Other resources related to the Periodic Table

Atomic Mass Of First 20 Elements

• Chemical Evolution of the Universe