Table of Atomic Masses
Values given to four significant figures where possible.
A value given in parentheses denotes the mass of the longest-lived isotope.
| Element
|
Symbol
|
Atomic Number
|
Atomic Mass
|
| Actinium
|
Ac
|
89
|
(227)
|
| Aluminum
|
Al
|
13
|
26.98
|
| Americium
|
Am
|
95
|
(243)
|
| Antimony
|
Sb
|
51
|
121.8
|
| Argon
|
Ar
|
18
|
39.95
|
| Arsenic
|
As
|
33
|
74.92
|
| Astatine
|
At
|
85
|
(210)
|
| Barium
|
Ba
|
56
|
137.3
|
| Berkelium
|
Bk
|
97
|
(247)
|
| Beryllium
|
Be
|
4
|
9.012
|
| Bismuth
|
Bi
|
83
|
209.0
|
| Boron
|
B
|
5
|
10.81
|
| Bromine
|
Br
|
35
|
79.90
|
| Cadmium
|
Cd
|
48
|
112.4
|
| Calcium
|
Ca
|
20
|
40.08
|
| Californium
|
Cf
|
98
|
(251)
|
| Carbon
|
C
|
6
|
12.01
|
| Cerium
|
Ce
|
58
|
140.1
|
| Cesium
|
Cs
|
55
|
132.9
|
| Chlorine
|
Cl
|
17
|
35.45
|
| Chromium
|
Cr
|
24
|
52.00
|
| Cobalt
|
Co
|
27
|
58.93
|
| Copper
|
Cu
|
29
|
63.55
|
| Curium
|
Cm
|
96
|
(247)
|
| Dysprosium
|
Dy
|
66
|
162.5
|
| Einsteinium
|
Es
|
99
|
(252)
|
| Erbium
|
Er
|
68
|
167.3
|
| Europium
|
Eu
|
63
|
152.0
|
| Fermium
|
Fm
|
100
|
(257)
|
| Fluorine
|
F
|
9
|
19.00
|
| Francium
|
Fr
|
87
|
(223)
|
| Gadolinium
|
Gd
|
64
|
157.3
|
| Gallium
|
Ga
|
31
|
69.72
|
| Germanium
|
Ge
|
32
|
72.59
|
| Gold
|
Au
|
79
|
197.0
|
| Hafnium
|
Hf
|
72
|
178.5
|
| Helium
|
He
|
2
|
4.003
|
| Holmium
|
Ho
|
67
|
164.9
|
| Hydrogen
|
H
|
1
|
1.008
|
| Indium
|
In
|
49
|
114.8
|
| Iodine
|
I
|
53
|
126.9
|
| Iridium
|
Ir
|
77
|
192.2
|
| Iron
|
Fe
|
26
|
55.85
|
| Krypton
|
Kr
|
36
|
83.80
|
| Lanthanum
|
La
|
57
|
138.9
|
| Lawrencium
|
Lr
|
103
|
(260)
|
| Lead
|
Pb
|
82
|
207.2
|
| Lithium
|
Li
|
3
|
6.941
|
| Lutetium
|
Lu
|
71
|
175.0
|
| Magnesium
|
Mg
|
12
|
24.31
|
| Manganese
|
Mn
|
25
|
54.94
|
| Mendelevium
|
Md
|
101
|
(258)
|
| Mercury
|
Hg
|
80
|
200.6
|
| Molybdenum
|
Mo
|
42
|
95.94
|
| Neodymium
|
Nd
|
60
|
144.2
|
| Neon
|
Ne
|
10
|
20.18
|
| Neptunium
|
Np
|
93
|
(237)
|
| Nickel
|
Ni
|
28
|
58.69
|
| Niobium
|
Nb
|
41
|
92.91
|
| Nitrogen
|
N
|
7
|
14.01
|
| Nobelium
|
No
|
102
|
(259)
|
| Osmium
|
Os
|
76
|
190.2
|
| Oxygen
|
O
|
8
|
16.00
|
| Palladium
|
Pd
|
46
|
106.4
|
| Phosphorus
|
P
|
15
|
30.97
|
| Platinum
|
Pt
|
78
|
195.1
|
| Plutonium
|
Pu
|
94
|
(244)
|
| Polonium
|
Po
|
84
|
(209)
|
| Potassium
|
K
|
19
|
39.10
|
| Praseodymium
|
Pr
|
59
|
140.9
|
| Promethium
|
Pm
|
61
|
(145)
|
| Protactinium
|
Pa
|
91
|
(231)
|
| Radium
|
Ra
|
88
|
226
|
| Radon
|
Rn
|
86
|
(222)
|
| Rhenium
|
Re
|
75
|
186.2
|
| Rhodium
|
Rh
|
45
|
102.9
|
| Rubidium
|
Rb
|
37
|
85.47
|
| Ruthenium
|
Ru
|
44
|
101.1
|
| Samarium
|
Sm
|
62
|
150.4
|
| Scandium
|
Sc
|
21
|
44.96
|
| Selenium
|
Se
|
34
|
78.96
|
| Silicon
|
Si
|
14
|
28.09
|
| Silver
|
Ag
|
47
|
107.9
|
| Sodium
|
Na
|
11
|
22.99
|
| Strontium
|
Sr
|
38
|
87.62
|
| Sulfur
|
S
|
16
|
32.07
|
| Tantalum
|
Ta
|
73
|
180.9
|
| Technetium
|
Tc
|
43
|
(98)
|
| Tellurium
|
Te
|
52
|
127.6
|
| Terbium
|
Tb
|
65
|
158.9
|
| Thallium
|
Tl
|
81
|
204.4
|
| Thorium
|
Th
|
90
|
232.0
|
| Thulium
|
Tm
|
69
|
168.9
|
| Tin
|
Sn
|
50
|
118.7
|
| Titanium
|
Ti
|
22
|
47.88
|
| Tungsten
|
W
|
74
|
183.9
|
| Uranium
|
U
|
92
|
238.0
|
| Vanadium
|
V
|
23
|
50.94
|
| Xenon
|
Xe
|
54
|
131.3
|
| Ytterbium
|
Yb
|
70
|
173.0
|
| Yttrium
|
Y
|
39
|
88.91
|
| Zinc
|
Zn
|
30
|
65.38
|
| Zirconium
|
Zr
|
40
|
91.22
|