-
ATOMIC WEIGHTS OF THE ELEMENTS 2007
These
tables
are
based
on
the
2007
table
at
Pure
Appl.
Chem.,
81
,
2131-2156
(2009) with changes to the values for
lutetium, molybdenum, nickel,
ytterbium
and
zinc
from
the
2005
table.
Mass
number
of
the
longest-lived
isotope of hassium
from
Phys. Rev. Lett.,
97
242501 (2006).
For the name
of element 112
see
Pure Appl. Chem.
2010,
82
, 753-755
/iupac/AtWt/
A
PDF
format
copy
(175
KBt)
of
the
2007
table
is
available
from
the
abstract
World Wide Web version of atomic weight
data originally prepared by G.
P. Moss,
from a file provided by D. R. Lide.
Previous
values
may
be
consulted
from
the
1993
table
,
the
1995
table
,
the
1997 table
,
the
1999 table
, the
2001 table
or the
2005 table
.
The
original paper should be consulted for details of
the half life of
the radioisotopes
quoted below. Also there is a report on the
different
isotopic compositions of some
non-terrestrial materials.
A number in
parentheses indicates the uncertainty in the last
digit of
the atomic weight.
See also a copy of the
periodic table
with atomic
weights to five
significant figures.
See also below the list in
Name order
.
List
of Elements in Atomic Number Order.
At
No
Symbol
Name
1
H
Hydrogen
2
He
Helium
3
Li
Lithium
4
Be
Beryllium
5
B
Boron
6
C
Carbon
7
N
Nitrogen
8
O
Oxygen
9
F
Fluorine
Atomic
Wt
Notes
1.00794(7)
1, 2, 3
4.002602(2)
1, 2
[6.941(2)]
1, 2, 3, 4
9.012182(3)
10.811(7)
1, 2,
3
12.0107(8)
1, 2
14.0067(2)
1, 2
15.9994(3)
1, 2
18.9984032(5)
10
11
12
13
14
15
Ne
Na
Mg
Al
Si
P
Neon
Sodium
Magnesium
Aluminium
Silicon
Phosphorus
20.1797(6)
1, 3
22.98976928(2)
24.3050(6)
26.9815386(8)
28.0855(3)
2
30.973762(2)
16
S
17
Cl
18
Ar
19
K
20
Ca
21
Sc
22
Ti
23
V
24
Cr
25
Mn
26
Fe
27
Co
28
Ni
29
Cu
30
Zn
31
Ga
32
Ge
33
As
34
Se
35
Br
36
Kr
37
Rb
38
Sr
39
Y
40
Zr
41
Nb
42
Mo
43
Tc
44
Ru
45
Rh
46
Pd
47
Ag
48
Cd
49
In
Sulfur
Chlorine
Argon
Potassium
Calcium
Scandium
Titanium
Vanadium
Chromium
Manganese
Iron
Cobalt
Nickel
Copper
Zinc
Gallium
Germanium
Arsenic
Selenium
Bromine
Krypton
Rubidium
Strontium
Yttrium
Zirconium
Niobium
Molybdenum
Technetium
Ruthenium
Rhodium
Palladium
Silver
Cadmium
Indium
32.065(5)
35.453(2)
39.948(1)
39.0983(1)
40.078(4)
44.955912(6)
47.867(1)
50.9415(1)
51.9961(6)
54.938045(5)
55.845(2)
58.933195(5)
58.6934(4)
63.546(3)
65.38(2)
69.723(1)
72.64(1)
74.92160(2)
78.96(3)
79.904(1)
83.798(2)
85.4678(3)
87.62(1)
88.90585(2)
91.224(2)
92.90638(2)
95.96(2)
[98]
101.07(2)
102.90550(2)
106.42(1)
107.8682(2)
112.411(8)
114.818(3)
1, 2
3
1, 2
1
1
2
1,
3
1
1, 2
1
1
5
1
1
1
1
50
51
52
53
54
55
56
57
Sn
Sb
Te
I
Xe
Cs
Ba
La
Tin
118.710(7)
1
Antimony
121.760(1)
1
Tellurium
127.60(3)
1
Iodine
126.90447(3)
Xenon
131.293(6)
1, 3
Caesium
132.9054519(2)
Barium
137.327(7)
Lanthanum
138.90547(7)
1
58
Ce
59
Pr
60
Nd
61
Pm
62
Sm
63
Eu
64
Gd
65
Tb
66
Dy
67
Ho
68
Er
69
Tm
70
Yb
71
Lu
72
Hf
73
Ta
74
W
75
Re
76
Os
77
Ir
78
Pt
79
Au
80
Hg
81
Tl
82
Pb
83
Bi
84
Po
85
At
86
Rn
87
Fr
88
Ra
89
Ac
Cerium
140.116(1)
Praseodymium
140.90765(2)
Neodymium
144.242(3)
Promethium
[145]
Samarium
150.36(2)
Europium
151.964(1)
Gadolinium
157.25(3)
Terbium
158.92535(2)
Dysprosium
162.500(1)
Holmium
164.93032(2)
Erbium
167.259(3)
Thulium
168.93421(2)
Ytterbium
173.054(5)
Lutetium
174.9668(1)
Hafnium
178.49(2)
Tantalum
180.94788(2)
Tungsten
183.84(1)
Rhenium
186.207(1)
Osmium
190.23(3)
Iridium
192.217(3)
Platinum
195.084(9)
Gold
196.966569(4)
Mercury
200.59(2)
Thallium
204.3833(2)
Lead
207.2(1)
Bismuth
208.98040(1)
Polonium
[209]
Astatine
[210]
Radon
[222]
Francium
[223]
Radium
[226]
Actinium
[227]
1
1
5
1
1
1
1
1
1
1
1
1, 2
5
5
5
5
5
5
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
118
Th
Pa
U
Np
Pu
Am
Cm
Bk
Cf
Es
Fm
Md
No
Lr
Rf
Db
Sg
Bh
Hs
Mt
Ds
Rg
Cn
Uut
Uuq
Uup
Uuh
Uuo
Thorium
232.03806(2)
Protactinium
231.03588(2)
Uranium
238.02891(3)
Neptunium
[237]
Plutonium
[244]
Americium
[243]
Curium
[247]
Berkelium
[247]
Californium
[251]
Einsteinium
[252]
Fermium
[257]
Mendelevium
[258]
Nobelium
[259]
Lawrencium
[262]
Rutherfordium
[265]
Dubnium
[268]
Seaborgium
[271]
Bohrium
[272]
Hassium
[270]
Meitnerium
[276]
Darmstadtium
[281]
Roentgenium
[280]
Copernicium
[285]
Ununtrium
[284]
Ununquadium
[289]
Ununpentium
[288]
Ununhexium
[293]
Ununoctium
[294]
1, 5
5
1, 3, 5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5, 6
5, 6
5, 6
5, 6
5, 6
5, 6
1.
Geological
specimens
are
known
in
which
the
element
has
an
isotopic
composition
outside
the
limits
for
normal
material.
The
difference
between
the
atomic
weight
of
the
element
in
such
specimens
and
that
given in
the Table may exceed the stated uncertainty.
2.
Range in
isotopic composition of normal terrestrial
material
prevents a more precise value
being given; the tabulated value
should
be applicable to any normal material.
3.
Modified
isotopic compositions may be found in commercially
available material because it has been
subject to an undisclosed
or
inadvertant isotopic fractionation. Substantial
deviations in
atomic
weight
of
the
element
from
that
given
in
the
Table
can
occur.
4.
Commercially
available
Li
materials
have
atomic
weights
that
range
between 6.939 and 6.996; if a more
accurate value is required, it