Appendix A: Atomic Masses

Table A1 Atomic Masses
Atomic Number, Z	Name	Atomic Mass Number, A	Symbol	Atomic Mass (u)	Percent Abundance or Decay Mode	Half-life, t_1/2
0	neutron	1	$n$	1.008 665	$β^{-}$	10.37 min
1	Hydrogen	1	$^{1} H$	1.007 825	99.985%
	Deuterium	2	$^{2} H or D$	2.014 102	0.015%
	Tritium	3	$^{3} H or T$	3.016 050	$β^{-}$	12.33 y
2	Helium	3	$^{3} He$	3.016 030	$1 . 38 \times 10^{- 4} %$
		4	$^{4} He$	4.002 603	$≈100%$
3	Lithium	6	$^{6} Li$	6.015 121	7.5%
		7	$^{7} Li$	7.016 003	92.5%
4	Beryllium	7	$^{7} Be$	7.016 928	EC	53.29 d
		9	$^{9} Be$	9.012 182	100%
5	Boron	10	$^{10} B$	10.012 937	19.9%
		11	$^{11} B$	11.009 305	80.1%
6	Carbon	11	$^{11} C$	11.011 432	EC, $β^{+}$
		12	$^{12} C$	12.000 000	98.90%
		13	$^{13} C$	13.003 355	1.10%
		14	$^{14} C$	14.003 241	$β^{-}$	5730 y
7	Nitrogen	13	$^{13} N$	13.005 738	$β^{+}$	9.96 min
		14	$^{14} N$	14.003 074	99.63%
		15	$^{15} N$	15.000 108	0.37%
8	Oxygen	15	$^{15} O$	15.003 065	EC, $β^{+}$	122 s
		16	$^{16} O$	15.994 915	99.76%
		18	$^{18} O$	17.999 160	0.200%
9	Fluorine	18	$^{18} F$	18.000 937	EC, $β^{+}$	1.83 h
		19	$^{19} F$	18.998 403	100%
10	Neon	20	$^{20} Ne$	19.992 435	90.51%
		22	$^{22} Ne$	21.991 383	9.22%
11	Sodium	22	$^{22} Na$	21.994 434	$β^{+}$	2.602 y
		23	$^{23} Na$	22.989 767	100%
		24	$^{24} Na$	23.990 961	$β^{-}$	14.96 h
12	Magnesium	24	$^{24} Mg$	23.985 042	78.99%
13	Aluminum	27	$^{27} Al$	26.981 539	100%
14	Silicon	28	$^{28} Si$	27.976 927	92.23%	2.62h
		31	$^{31} Si$	30.975 362	$β^{-}$
15	Phosphorus	31	$^{31} P$	30.973 762	100%
		32	$^{32} P$	31.973 907	$β^{-}$	14.28 d
16	Sulfur	32	$^{32} S$	31.972 070	95.02%
		35	$^{35} S$	34.969 031	$β^{-}$	87.4 d
17	Chlorine	35	$^{35} Cl$	34.968 852	75.77%
		37	$^{37} Cl$	36.965 903	24.23%
18	Argon	40	$^{40} Ar$	39.962 384	99.60%
19	Potassium	39	$^{39} K$	38.963 707	93.26%
		40	$^{40} K$	39.963 999	0.0117%, EC, $β^{-}$	$1 . 28 \times 10^{9} y$
20	Calcium	40	$^{40} Ca$	39.962 591	96.94%
21	Scandium	45	$^{45} Sc$	44.955 910	100%
22	Titanium	48	$^{48} Ti$	47.947 947	73.8%
23	Vanadium	51	$^{51} V$	50.943 962	99.75%
24	Chromium	52	$^{52} Cr$	51.940 509	83.79%
25	Manganese	55	$^{55} Mn$	54.938 047	100%
26	Iron	56	$^{56} Fe$	55.934 939	91.72%
27	Cobalt	59	$^{59} Co$	58.933 198	100%
		60	$^{60} Co$	59.933 819	$β^{-}$	5.271 y
28	Nickel	58	$^{58} Ni$	57.935 346	68.27%
		60	$^{60} Ni$	59.930 788	26.10%
29	Copper	63	$^{63} Cu$	62.939 598	69.17%
		65	$^{65} Cu$	64.927 793	30.83%
30	Zinc	64	$^{64} Zn$	63.929 145	48.6%
		66	$^{66} Zn$	65.926 034	27.9%
31	Gallium	69	$^{69} Ga$	68.925 580	60.1%
32	Germanium	72	$^{72} Ge$	71.922 079	27.4%
		74	$^{74} Ge$	73.921 177	36.5%
33	Arsenic	75	$^{75} As$	74.921 594	100%
34	Selenium	80	$^{80} Se$	79.916 520	49.7%
35	Bromine	79	$^{79} Br$	78.918 336	50.69%
36	Krypton	84	$^{84} Kr$	83.911 507	57.0%
37	Rubidium	85	$^{85} Rb$	84.911 794	72.17%
38	Strontium	86	$^{86} Sr$	85.909 267	9.86%
		88	$^{88} Sr$	87.905 619	82.58%
		90	$^{90} Sr$	89.907 738	$β^{-}$	28.8 y
39	Yttrium	89	$^{89} Y$	88.905 849	100%
		90	$^{90} Y$	89.907 152	$β^{-}$	64.1 h
40	Zirconium	90	$^{90} Zr$	89.904 703	51.45%
41	Niobium	93	$^{93} Nb$	92.906 377	100%
42	Molybdenum	98	$^{98} Mo$	97.905 406	24.13%
43	Technetium	98	$^{98} Tc$	97.907 215	$β^{-}$	$4 . 2 \times 10^{6} y$
44	Ruthenium	102	$^{102} Ru$	101.904 348	31.6%
45	Rhodium	103	$^{103} Rh$	102.905 500	100%
46	Palladium	106	$^{106} Pd$	105.903 478	27.33%
47	Silver	107	$^{107} Ag$	106.905 092	51.84%
		109	$^{109} Ag$	108.904 757	48.16%
48	Cadmium	114	$^{114} Cd$	113.903 357	28.73%
49	Indium	115	$^{115} In$	114.903 880	95.7%, $β^{-}$	$4 . 4 \times 10^{14} y$
50	Tin	120	$^{120} Sn$	119.902 200	32.59%
51	Antimony	121	$^{121} Sb$	120.903 821	57.3%
52	Tellurium	130	$^{130} Te$	129.906 229	33.8%, $β^{-}$	$2 . 5 \times 10^{21} y$
53	Iodine	127	$^{127} I$	126.904 473	100%
		131	$^{131} I$	130.906 114	$β^{-}$	8.040 d
54	Xenon	132	$^{132} Xe$	131.904 144	26.9%
		136	$^{136} Xe$	135.907 214	8.9%
55	Cesium	133	$^{133} Cs$	132.905 429	100%
		134	$^{134} Cs$	133.906 696	EC, $β^{-}$	2.06 y
56	Barium	137	$^{137} Ba$	136.905 812	11.23%
		138	$^{138} Ba$	137.905 232	71.70%
57	Lanthanum	139	$^{139} La$	138.906 346	99.91%
58	Cerium	140	$^{140} Ce$	139.905 433	88.48%
59	Praseodymium	141	$^{141} Pr$	140.907 647	100%
60	Neodymium	142	$^{142} Nd$	141.907 719	27.13%
61	Promethium	145	$^{145} Pm$	144.912 743	EC, $α$	17.7 y
62	Samarium	152	$^{152} Sm$	151.919 729	26.7%
63	Europium	153	$^{153} Eu$	152.921 225	52.2%
64	Gadolinium	158	$^{158} Gd$	157.924 099	24.84%
65	Terbium	159	$^{159} Tb$	158.925 342	100%
66	Dysprosium	164	$^{164} Dy$	163.929 171	28.2%
67	Holmium	165	$^{165} Ho$	164.930 319	100%
68	Erbium	166	$^{166} Er$	165.930 290	33.6%
69	Thulium	169	$^{169} Tm$	168.934 212	100%
70	Ytterbium	174	$^{174} Yb$	173.938 859	31.8%
71	Lutecium	175	$^{175} Lu$	174.940 770	97.41%
72	Hafnium	180	$^{180} Hf$	179.946 545	35.10%
73	Tantalum	181	$^{181} Ta$	180.947 992	99.98%
74	Tungsten	184	$^{184} W$	183.950 928	30.67%
75	Rhenium	187	$^{187} Re$	186.955 744	62.6%, $β^{-}$	$4 . 6 \times 10^{10} y$
76	Osmium	191	$^{191} Os$	190.960 920	$β^{-}$	15.4 d
		192	$^{192} Os$	191.961 467	41.0%
77	Iridium	191	$^{191} Ir$	190.960 584	37.3%
		193	$^{193} Ir$	192.962 917	62.7%
78	Platinum	195	$^{195} Pt$	194.964 766	33.8%
79	Gold	197	$^{197} Au$	196.966 543	100%
		198	$^{198} Au$	197.968 217	$β^{-}$	2.696 d
80	Mercury	199	$^{199} Hg$	198.968 253	16.87%
		202	$^{202} Hg$	201.970 617	29.86%
81	Thallium	205	$^{205} Tl$	204.974 401	70.48%
82	Lead	206	$^{206} Pb$	205.974 440	24.1%
		207	$^{207} Pb$	206.975 872	22.1%
		208	$^{208} Pb$	207.976 627	52.4%
		210	$^{210} Pb$	209.984 163	$α, β^{-}$	22.3 y
		211	$^{211} Pb$	210.988 735	$β^{-}$	36.1 min
		212	$^{212} Pb$	211.991 871	$β^{-}$	10.64 h
83	Bismuth	209	$^{209} Bi$	208.980 374	100%
		211	$^{211} Bi$	210.987 255	$α, β^{-}$	2.14 min
84	Polonium	210	$^{210} Po$	209.982 848	$α$	138.38 d
85	Astatine	218	$^{218} At$	218.008 684	$α, β^{-}$	1.6 s
86	Radon	222	$^{222} Rn$	222.017 570	$α$	3.82 d
87	Francium	223	$^{223} Fr$	223.019 733	$α, β^{-}$	21.8 min
88	Radium	226	$^{226} Ra$	226.025 402	$α$	$1 . 60 \times 10^{3} y$
89	Actinium	227	$^{227} Ac$	227.027 750	$α, β^{-}$	21.8 y
90	Thorium	228	$^{228} Th$	228.028 715	$α$	1.91 y
		232	$^{232} Th$	232.038 054	100%, $α$	$1 . 41 \times 10^{10} y$
91	Protactinium	231	$^{231} Pa$	231.035 880	$α$	$3 . 28 \times 10^{4} y$
92	Uranium	233	$^{233} U$	233.039 628	$α$	$1 . 59 \times 10^{3} y$
		235	$^{235} U$	235.043 924	0.720%, $α$	$7 . 04 \times 10^{8} y$
		236	$^{236} U$	236.045 562	$α$	$2 . 34 \times 10^{7} y$
		238	$^{238} U$	238.050 784	99.2745%, $α$	$4 . 47 \times 10^{9} y$
		239	$^{239} U$	239.054 289	$β^{-}$	23.5 min
93	Neptunium	239	$^{239} Np$	239.052 933	$β^{-}$	2.355 d
94	Plutonium	239	$^{239} Pu$	239.052 157	$α$	$2 . 41 \times 10^{4} y$
95	Americium	243	$^{243} Am$	243.061 375	$α,$ fission	$7 . 37 \times 10^{3} y$
96	Curium	245	$^{245} Cm$	245.065 483	$α$	$8 . 50 \times 10^{3} y$
97	Berkelium	247	$^{247} Bk$	247.070 300	$α$	$1 . 38 \times 10^{3} y$
98	Californium	249	$^{249} Cf$	249.074 844	$α$	351 y
99	Einsteinium	254	$^{254} Es$	254.088 019	$α, β^{-}$	276 d
100	Fermium	253	$^{253} Fm$	253.085 173	EC, $α$	3.00 d
101	Mendelevium	255	$^{255} Md$	255.091 081	EC, $α$	27 min
102	Nobelium	255	$^{255} No$	255.093 260	EC, $α$	3.1 min
103	Lawrencium	257	$^{257} Lr$	257.099 480	EC, $α$	0.646 s
104	Rutherfordium	261	$^{261} Rf$	261.108 690	$α$	1.08 min
105	Dubnium	262	$^{262} Db$	262.113 760	$α,$ fission	34 s
106	Seaborgium	263	$^{263} Sg$	263.11 86	$α,$ fission	0.8 s
107	Bohrium	262	$^{262} Bh$	262.123 1	$α$	0.102 s
108	Hassium	264	$^{264} Hs$	264.128 5	$α$	0.08 ms
109	Meitnerium	266	$^{266} Mt$	266.137 8	$α$	3.4 ms