Atomic Masses

Atomic Number, Z	Name	Atomic Mass Number, A	Atomic Mass (u)	Percent Abundance or Decay Mode	Half-life, t_1/2
0	neutron	1	1.008 665		10.37 min
1	Hydrogen	1	1.007 825	99.985%
	Deuterium	2	2.014 102	0.015%
	Tritium	3	3.016 050		12.33 y
2	Helium	3	3.016 030
		4	4.002 603
3	Lithium	6	6.015 121	7.5%
		7	7.016 003	92.5%
4	Beryllium	7	7.016 928	EC	53.29 d
		9	9.012 182	100%
5	Boron	10	10.012 937	19.9%
		11	11.009 305	80.1%
6	Carbon	11	11.011 432	EC,
		12	12.000 000	98.90%
		13	13.003 355	1.10%
		14	14.003 241		5730 y
7	Nitrogen	13	13.005 738		9.96 min
		14	14.003 074	99.63%
		15	15.000 108	0.37%
8	Oxygen	15	15.003 065	EC,	122 s
		16	15.994 915	99.76%
		18	17.999 160	0.200%
9	Fluorine	18	18.000 937	EC,	1.83 h
		19	18.998 403	100%
10	Neon	20	19.992 435	90.51%
		22	21.991 383	9.22%
11	Sodium	22	21.994 434		2.602 y
		23	22.989 767	100%
		24	23.990 961		14.96 h
12	Magnesium	24	23.985 042	78.99%
13	Aluminum	27	26.981 539	100%
14	Silicon	28	27.976 927	92.23%	2.62h
		31	30.975 362
15	Phosphorus	31	30.973 762	100%
		32	31.973 907		14.28 d
16	Sulfur	32	31.972 070	95.02%
		35	34.969 031		87.4 d
17	Chlorine	35	34.968 852	75.77%
		37	36.965 903	24.23%
18	Argon	40	39.962 384	99.60%
19	Potassium	39	38.963 707	93.26%
		40	39.963 999	0.0117%, EC,
20	Calcium	40	39.962 591	96.94%
21	Scandium	45	44.955 910	100%
22	Titanium	48	47.947 947	73.8%
23	Vanadium	51	50.943 962	99.75%
24	Chromium	52	51.940 509	83.79%
25	Manganese	55	54.938 047	100%
26	Iron	56	55.934 939	91.72%
27	Cobalt	59	58.933 198	100%
		60	59.933 819		5.271 y
28	Nickel	58	57.935 346	68.27%
		60	59.930 788	26.10%
29	Copper	63	62.939 598	69.17%
		65	64.927 793	30.83%
30	Zinc	64	63.929 145	48.6%
		66	65.926 034	27.9%
31	Gallium	69	68.925 580	60.1%
32	Germanium	72	71.922 079	27.4%
		74	73.921 177	36.5%
33	Arsenic	75	74.921 594	100%
34	Selenium	80	79.916 520	49.7%
35	Bromine	79	78.918 336	50.69%
36	Krypton	84	83.911 507	57.0%
37	Rubidium	85	84.911 794	72.17%
38	Strontium	86	85.909 267	9.86%
		88	87.905 619	82.58%
		90	89.907 738		28.8 y
39	Yttrium	89	88.905 849	100%
		90	89.907 152		64.1 h
40	Zirconium	90	89.904 703	51.45%
41	Niobium	93	92.906 377	100%
42	Molybdenum	98	97.905 406	24.13%
43	Technetium	98	97.907 215
44	Ruthenium	102	101.904 348	31.6%
45	Rhodium	103	102.905 500	100%
46	Palladium	106	105.903 478	27.33%
47	Silver	107	106.905 092	51.84%
		109	108.904 757	48.16%
48	Cadmium	114	113.903 357	28.73%
49	Indium	115	114.903 880	95.7%,
50	Tin	120	119.902 200	32.59%
51	Antimony	121	120.903 821	57.3%
52	Tellurium	130	129.906 229	33.8%,
53	Iodine	127	126.904 473	100%
		131	130.906 114		8.040 d
54	Xenon	132	131.904 144	26.9%
		136	135.907 214	8.9%
55	Cesium	133	132.905 429	100%
		134	133.906 696	EC,	2.06 y
56	Barium	137	136.905 812	11.23%
		138	137.905 232	71.70%
57	Lanthanum	139	138.906 346	99.91%
58	Cerium	140	139.905 433	88.48%
59	Praseodymium	141	140.907 647	100%
60	Neodymium	142	141.907 719	27.13%
61	Promethium	145	144.912 743	EC,	17.7 y
62	Samarium	152	151.919 729	26.7%
63	Europium	153	152.921 225	52.2%
64	Gadolinium	158	157.924 099	24.84%
65	Terbium	159	158.925 342	100%
66	Dysprosium	164	163.929 171	28.2%
67	Holmium	165	164.930 319	100%
68	Erbium	166	165.930 290	33.6%
69	Thulium	169	168.934 212	100%
70	Ytterbium	174	173.938 859	31.8%
71	Lutecium	175	174.940 770	97.41%
72	Hafnium	180	179.946 545	35.10%
73	Tantalum	181	180.947 992	99.98%
74	Tungsten	184	183.950 928	30.67%
75	Rhenium	187	186.955 744	62.6%,
76	Osmium	191	190.960 920		15.4 d
		192	191.961 467	41.0%
77	Iridium	191	190.960 584	37.3%
		193	192.962 917	62.7%
78	Platinum	195	194.964 766	33.8%
79	Gold	197	196.966 543	100%
		198	197.968 217		2.696 d
80	Mercury	199	198.968 253	16.87%
		202	201.970 617	29.86%
81	Thallium	205	204.974 401	70.48%
82	Lead	206	205.974 440	24.1%
		207	206.975 872	22.1%
		208	207.976 627	52.4%
		210	209.984 163		22.3 y
		211	210.988 735		36.1 min
		212	211.991 871		10.64 h
83	Bismuth	209	208.980 374	100%
		211	210.987 255		2.14 min
84	Polonium	210	209.982 848		138.38 d
85	Astatine	218	218.008 684		1.6 s
86	Radon	222	222.017 570		3.82 d
87	Francium	223	223.019 733		21.8 min
88	Radium	226	226.025 402
89	Actinium	227	227.027 750		21.8 y
90	Thorium	228	228.028 715		1.91 y
		232	232.038 054	100%,
91	Protactinium	231	231.035 880
92	Uranium	233	233.039 628
		235	235.043 924	0.720%,
		236	236.045 562
		238	238.050 784	99.2745%,
		239	239.054 289		23.5 min
93	Neptunium	239	239.052 933		2.355 d
94	Plutonium	239	239.052 157
95	Americium	243	243.061 375	fission
96	Curium	245	245.065 483
97	Berkelium	247	247.070 300
98	Californium	249	249.074 844		351 y
99	Einsteinium	254	254.088 019		276 d
100	Fermium	253	253.085 173	EC,	3.00 d
101	Mendelevium	255	255.091 081	EC,	27 min
102	Nobelium	255	255.093 260	EC,	3.1 min
103	Lawrencium	257	257.099 480	EC,	0.646 s
104	Rutherfordium	261	261.108 690		1.08 min
105	Dubnium	262	262.113 760	fission	34 s
106	Seaborgium	263	263.11 86	fission	0.8 s
107	Bohrium	262	262.123 1		0.102 s
108	Hassium	264	264.128 5		0.08 ms
109	Meitnerium	266	266.137 8		3.4 ms

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