Appendix A Atomic Masses

Douglas College Physics Department; OpenStax

Appendix A 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	¹H	1.007 825	99.985%
	Deuterium	2	²H or D	2.014 102	0.015%
	Tritium	3	³H or T	3.016 050	β-	12.33 y
2	Helium	3	³He	3.016 030	1.38×10^-4%
		4	⁴He	4.002 603	≈100%
3	Lithium	6	⁶Li	6.015 121	7.5%
		7	7Li	7.016 003	92.5%
4	Beryllium	7	⁷Be	7.016 928	EC	53.29 d
		9	⁹Be	9.012 182	100%
5	Boron	10	¹⁰B	10.012 937	19.9%
		11	¹¹B	11.009 305	80.1%
6	Carbon	11	¹¹C	11.011 432	EC, β+
		12	12C	12.000 000	98.90%
		13	13C	13.003 355	1.10%
		14	¹⁴C	14.003 241	β-	5730 y
7	Nitrogen	13	¹³N	13.005 738	β+	9.96 min
		14	14N	14.003 074	99.63%
		15	15N	15.000 108	0.37%
8	Oxygen	15	$^{15} \textbf{O}$	15.003 065	EC, β+	122 s
		16	$^{16} \textbf{O}$	15.994 915	99.76%
		18	$^{18} \textbf{O}$	17.999 160	0.200%
9	Fluorine	18	$^{18} \textbf{F}$	18.000 937	EC, β+	1.83 h
		19	$^{19} \textbf{F}$	18.998 403	100%
10	Neon	20	$^{20} \textbf{Ne}$	19.992 435	90.51%
		22	$^{22} \textbf{Ne}$	21.991 383	9.22%
11	Sodium	22	$^{22} \textbf{Na}$	21.994 434	β+	2.602 y
		23	$^{23} \textbf{Na}$	22.989 767	100%
		24	$^{24} \textbf{Na}$	23.990 961	β-	14.96 h
12	Magnesium	24	$^{24} \textbf{Mg}$	23.985 042	78.99%
13	Aluminum	27	$^{27} \textbf{Al}$	26.981 539	100%
14	Silicon	28	$^{28} \textbf{Si}$	27.976 927	92.23%	2.62h
		31	$^{31} \textbf{Si}$	30.975 362	β-
15	Phosphorus	31	$^{31} \textbf{P}$	30.973 762	100%
		32	$^{32} \textbf{P}$	31.973 907	β-	14.28 d
16	Sulfur	32	$^{32} \textbf{S}$	31.972 070	95.02%
		35	$^{35} \textbf{S}$	34.969 031	β-	87.4 d
17	Chlorine	35	$^{35} \textbf{Cl}$	34.968 852	75.77%
		37	$^{37} \textbf{Cl}$	36.965 903	24.23%
18	Argon	40	$^{40} \textbf{Ar}$	39.962 384	99.60%
19	Potassium	39	$^{39} \textbf{K}$	38.963 707	93.26%
		40	$^{40} \textbf{K}$	39.963 999	0.0117%, EC, β-	$1.28 \times 10^9 \text{y}$
20	Calcium	40	$^{40} \textbf{Ca}$	39.962 591	96.94%
21	Scandium	45	$^{45} \textbf{Sc}$	44.955 910	100%
22	Titanium	48	$^{48} \textbf{Ti}$	47.947 947	73.8%
23	Vanadium	51	$^{51} \textbf{V}$	50.943 962	99.75%
24	Chromium	52	$^{52} \textbf{Cr}$	51.940 509	83.79%
25	Manganese	55	$^{55} \textbf{Mn}$	54.938 047	100%
26	Iron	56	$^{56} \textbf{Fe}$	55.934 939	91.72%
27	Cobalt	59	$^{59} \textbf{Co}$	58.933 198	100%
		60	$^{60} \textbf{Co}$	59.933 819	β-	5.271 y
28	Nickel	58	$^{58} \textbf{Ni}$	57.935 346	68.27%
		60	$^{60} \textbf{Ni}$	59.930 788	26.10%
29	Copper	63	$^{63} \textbf{Cu}$	62.939 598	69.17%
		65	$^{65} \textbf{Cu}$	64.927 793	30.83%
30	Zinc	64	$^{64} \textbf{Zn}$	63.929 145	48.6%
		66	$^{66} \textbf{Zn}$	65.926 034	27.9%
31	Gallium	69	$^{69} \textbf{Ga}$	68.925 580	60.1%
32	Germanium	72	$^{72} \textbf{Ge}$	71.922 079	27.4%
		74	$^{74} \textbf{Ge}$	73.921 177	36.5%
33	Arsenic	75	$^{75} \textbf{As}$	74.921 594	100%
34	Selenium	80	$^{80} \textbf{Se}$	79.916 520	49.7%
35	Bromine	79	$^{79} \textbf{Br}$	78.918 336	50.69%
36	Krypton	84	$^{84} \textbf{Kr}$	83.911 507	57.0%
37	Rubidium	85	$^{85} \textbf{Rb}$	84.911 794	72.17%
38	Strontium	86	$^{86} \textbf{Sr}$	85.909 267	9.86%
		88	$^{88} \textbf{Sr}$	87.905 619	82.58%
		90	$^{90} \textbf{Sr}$	89.907 738	β-	28.8 y
39	Yttrium	89	$^{89} \textbf{Y}$	88.905 849	100%
		90	$^{90} \textbf{Y}$	89.907 152	β-	64.1 h
40	Zirconium	90	$^{90} \textbf{Zr}$	89.904 703	51.45%
41	Niobium	93	$^{93} \textbf{Nb}$	92.906 377	100%
42	Molybdenum	98	$^{98} \textbf{Mo}$	97.905 406	24.13%
43	Technetium	98	⁹⁸Tc	97.907 215	β-	4.2×10⁶ yr
44	Ruthenium	102	$^{102} \textbf{Ru}$	101.904 348	31.6%
45	Rhodium	103	$^{103} \textbf{Rh}$	102.905 500	100%
46	Palladium	106	$^{106} \textbf{Pd}$	105.903 478	27.33%
47	Silver	107	$^{107} \textbf{Ag}$	106.905 092	51.84%
		109	$^{109} \textbf{Ag}$	108.904 757	48.16%
48	Cadmium	114	$^{114} \textbf{Cd}$	113.903 357	28.73%
49	Indium	115	$^{115} \textbf{In}$	114.903 880	95.7%, β-	$4.4 \times 10^{14} \text{y}$
50	Tin	120	$^{120} \textbf{Sn}$	119.902 200	32.59%
51	Antimony	121	$^{121} \textbf{Sb}$	120.903 821	57.3%
52	Tellurium	130	$^{130} \textbf{Te}$	129.906 229	33.8%, β-	$2.5 \times 10^{21} \text{y}$
53	Iodine	127	$^{127} \textbf{I}$	126.904 473	100%
		131	$^{131} \textbf{I}$	130.906 114	β-	8.040 d
54	Xenon	132	$^{132} \textbf{Xe}$	131.904 144	26.9%
		136	$^{136} \textbf{Xe}$	135.907 214	8.9%
55	Cesium	133	$^{133} \textbf{Cs}$	132.905 429	100%
		134	$^{134} \textbf{Cs}$	133.906 696	EC, β-	2.06 y
56	Barium	137	$^{137} \textbf{Ba}$	136.905 812	11.23%
		138	$^{138} \textbf{Ba}$	137.905 232	71.70%
57	Lanthanum	139	$^{139} \textbf{La}$	138.906 346	99.91%
58	Cerium	140	$^{140} \textbf{Ce}$	139.905 433	88.48%
59	Praseodymium	141	$^{141} \textbf{Pr}$	140.907 647	100%
60	Neodymium	142	$^{142} \textbf{Nd}$	141.907 719	27.13%
61	Promethium	145	$^{145} \textbf{Pm}$	144.912 743	EC, α	17.7 y
62	Samarium	152	$^{152} \textbf{Sm}$	151.919 729	26.7%
63	Europium	153	$^{153} \textbf{Eu}$	152.921 225	52.2%
64	Gadolinium	158	$^{158} \textbf{Gd}$	157.924 099	24.84%
65	Terbium	159	$^{159} \textbf{Tb}$	158.925 342	100%
66	Dysprosium	164	$^{164} \textbf{Dy}$	163.929 171	28.2%
67	Holmium	165	$^{165} \textbf{Ho}$	164.930 319	100%
68	Erbium	166	$^{166} \textbf{Er}$	165.930 290	33.6%
69	Thulium	169	$^{169} \textbf{Tm}$	168.934 212	100%
70	Ytterbium	174	$^{174} \textbf{Yb}$	173.938 859	31.8%
71	Lutecium	175	$^{175} \textbf{Lu}$	174.940 770	97.41%
72	Hafnium	180	$^{180} \textbf{Hf}$	179.946 545	35.10%
73	Tantalum	181	$^{181} \textbf{Ta}$	180.947 992	99.98%
74	Tungsten	184	$^{184} \textbf{W}$	183.950 928	30.67%
75	Rhenium	187	$^{187} \textbf{Re}$	186.955 744	62.6%, β-	$4.6 \times 10^{10} \text{y}$
76	Osmium	191	$^{191} \textbf{Os}$	190.960 920	β-	15.4 d
		192	$^{192} \textbf{Os}$	191.961 467	41.0%
77	Iridium	191	$^{191} \textbf{Ir}$	190.960 584	37.3%
		193	$^{193} \textbf{Ir}$	192.962 917	62.7%
78	Platinum	195	$^{195} \textbf{Pt}$	194.964 766	33.8%
79	Gold	197	$^{197} \textbf{Au}$	196.966 543	100%
		198	$^{198} \textbf{Au}$	197.968 217	β-	2.696 d
80	Mercury	199	$^{199} \textbf{Hg}$	198.968 253	16.87%
		202	$^{202} \textbf{Hg}$	201.970 617	29.86%
81	Thallium	205	$^{205} \textbf{Tl}$	204.974 401	70.48%
82	Lead	206	$^{206} \textbf{Pb}$	205.974 440	24.1%
		207	$^{207} \textbf{Pb}$	206.975 872	22.1%
		208	$^{208} \textbf{Pb}$	207.976 627	52.4%
		210	$^{210} \textbf{Pb}$	209.984 163	α, β-	22.3 y
		211	$^{211} \textbf{Pb}$	210.988 735	β-	36.1 min
		212	$^{212} \textbf{Pb}$	211.991 871	β-	10.64 h
83	Bismuth	209	$^{209} \textbf{Bi}$	208.980 374	100%
		211	$^{211} \textbf{Bi}$	210.987 255	α, β-	2.14 min
84	Polonium	210	$^{210} \textbf{Po}$	209.982 848	α	138.38 d
85	Astatine	218	$^{218} \textbf{At}$	218.008 684	α, β-	1.6 s
86	Radon	222	$^{222} \textbf{Rn}$	222.017 570	α	3.82 d
87	Francium	223	$^{223} \textbf{Fr}$	223.019 733	α, β-	21.8 min
88	Radium	226	$^{226} \textbf{Ra}$	226.025 402	α	$1.60 \times 10^3 \text{y}$
89	Actinium	227	$^{227} \textbf{Ac}$	227.027 750	α, β-	21.8 y
90	Thorium	228	$^{228} \textbf{Th}$	228.028 715	α	1.91 y
		232	$^{232} \textbf{Th}$	232.038 054	100%, α	$1.41 \times 10^{10} \text{y}$
91	Protactinium	231	$^{231} \textbf{Pa}$	231.035 880	α	$3.28 \times 10^4 \text{y}$
92	Uranium	233	$^{233} \textbf{U}$	233.039 628	α	$1.59 \times 10^3 \text{y}$
		235	$^{235} \textbf{U}$	235.043 924	0.720%, α	$7.04 \times 10^8 \text{y}$
		236	$^{236} \textbf{U}$	236.045 562	α	$2.34 \times 10^7 \text{y}$
		238	$^{238} \textbf{U}$	238.050 784	99.2745%, α	$4.47 \times 10^9 \text{y}$
		239	$^{239} \textbf{U}$	239.054 289	β-	23.5 min
93	Neptunium	239	$^{239} \textbf{Np}$	239.052 933	β-	2.355 d
94	Plutonium	239	$^{239} \textbf{Pu}$	239.052 157	α	$2.41 \times 10^4 \text{y}$
95	Americium	243	$^{243} \textbf{Am}$	243.061 375	α, fission	$7.37 \times 10^3 \text{y}$
96	Curium	245	$^{245} \textbf{Cm}$	245.065 483	α	$8.50 \times 10^3 \text{y}$
97	Berkelium	247	$^{247} \textbf{Bk}$	247.070 300	α	$1.38 \times 10^3 \text{y}$
98	Californium	249	$^{249} \textbf{Cf}$	249.074 844	α	351 y
99	Einsteinium	254	$^{254} \textbf{Es}$	254.088 019	α, β-	276 d
100	Fermium	253	$^{253} \textbf{Fm}$	253.085 173	EC, α	3.00 d
101	Mendelevium	255	$^{255} \textbf{Md}$	255.091 081	EC, α	27 min
102	Nobelium	255	$^{255} \textbf{No}$	255.093 260	EC, α	3.1 min
103	Lawrencium	257	$^{257} \textbf{Lr}$	257.099 480	EC, α	0.646 s
104	Rutherfordium	261	$^{261} \textbf{Rf}$	261.108 690	α	1.08 min
105	Dubnium	262	$^{262} \textbf{Db}$	262.113 760	α, fission	34 s
106	Seaborgium	263	$^{263} \textbf{Sg}$	263.11 86	α, fission	0.8 s
107	Bohrium	262	$^{262} \textbf{Bh}$	262.123 1	α	0.102 s
108	Hassium	264	²⁶⁴Hs	264.128 5	α	0.08 ms
109	Meitnerium	266	²⁶⁶Mt	266.137 8	α	3.4 ms
Table 1: Atomic Masses

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