page1
1
H
hydrogen
1.0080
± 0.0002
1
18
3
Li
lithium
6.94
± 0.06
4
Be
beryllium
9.0122
± 0.0001
11
Na
sodium
22.990
± 0.001
12
Mg
magnesium
24.305
± 0.002
19
K
potassium
39.098
± 0.001
20
Ca
calcium
40.078
± 0.004
37
Rb
rubidium
85.468
± 0.001
38
Sr
strontium
87.62
± 0.01
38
strontium
87.62
± 0.01
55
Cs
caesium
132.91
± 0.01
55
caesium
132.91
± 0.01
56
Ba
barium
137.33
± 0.01
87
Fr
francium
[223]
88
Ra
radium
[226]
5
B
boron
10.81
± 0.02
13
Al
aluminium
26.982
± 0.001
31
Ga
gallium
69.723
± 0.001
49
In
indium
114.82
± 0.01
81
Tl
thallium
204.38
± 0.01
6
C
carbon
12.011
± 0.002
14
Si
silicon
28.085
± 0.001
32
Ge
germanium
72.630
± 0.008
50
Sn
tin
118.71
± 0.01
82
Pb
lead
207.2
± 1.1
7
N
nitrogen
14.007
± 0.001
15
P
phosphorus
30.974
± 0.001
33
As
arsenic
74.922
± 0.001
51
Sb
antimony
121.76
± 0.01
83
Bi
bismuth
208.98
± 0.01
8
O
oxygen
15.999
± 0.001
16
S
sulfur
32.06
± 0.02
34
Se
selenium
78.971
± 0.008
52
Te
tellurium
127.60
± 0.03
84
Po
polonium
[209]
9
F
fluorine
18.998
± 0.001
17
Cl
chlorine
35.45
± 0.01
35
Br
bromine
79.904
± 0.003
53
I
iodine
126.90
± 0.01
85
At
astatine
[210]
10
Ne
neon
20.180
± 0.001
2
He
helium
4.0026
± 0.0001
18
Ar
argon
39.95
± 0.16
36
Kr
krypton
83.798
± 0.002
54
Xe
xenon
131.29
± 0.01
86
Rn
radon
[222]
22
Ti
titanium
47.867
± 0.001
22
titanium
47.867
± 0.001
40
Zr
zirconium
91.224
± 0.002
72
Hf
hafnium
178.49
± 0.01
104
Rf
rutherfordium
[267]
23
V
vanadium
50.942
± 0.001
41
Nb
niobium
92.906
± 0.001
73
Ta
tantalum
180.95
± 0.01
105
Db
dubnium
[268]
24
Cr
chromium
51.996
± 0.001
24
Cr
chromium
51.996
± 0.001
42
Mo
molybdenum
95.95
± 0.01
74
W
tungsten
183.84
± 0.01
106
Sg
seaborgium
[269]
25
Mn
manganese
54.938
± 0.001
43
Tc
technetium
[97]
75
Re
rhenium
186.21
± 0.01
107
Bh
bohrium
[270]
26
Fe
iron
55.845
± 0.002
44
Ru
ruthenium
101.07
± 0.02
76
Os
osmium
190.23
± 0.03
108
Hs
hassium
[269]
27
Co
cobalt
58.933
± 0.001
45
Rh
rhodium
102.91
± 0.01
77
Ir
iridium
192.22
± 0.01
109
Mt
meitnerium
[277]
28
Ni
nickel
58.693
± 0.001
46
Pd
palladium
106.42
± 0.01
78
Pt
platinum
195.08
± 0.02
110
Ds
darmstadtium
[281]
29
Cu
copper
63.546
± 0.003
47
Ag
silver
107.87
± 0.01
79
Au
gold
196.97
± 0.01
30
Zn
zinc
65.38
± 0.02
48
Cd
cadmium
112.41
± 0.01
80
Hg
mercury
200.59
± 0.01
111
Rg
roentgenium
[282]
112
Cn
copernicium
[285]
114
Fl
flerovium
[290]
113
Nh
nihonium
[286]
115
Mc
moscovium
[290]
117
Ts
tennessine
[294]
118
Og
oganesson
[294]
116
Lv
livermorium
[293]
57
La
lanthanum
138.91
± 0.01
58
Ce
cerium
140.12
± 0.01
59
Pr
praseodymium
140.91
± 0.01
60
Nd
neodymium
144.24
± 0.01
61
Pm
promethium
[145]
62
Sm
samarium
150.36
± 0.02
63
Eu
europium
151.96
± 0.01
64
Gd
gadolinium
157.25
± 0.03
65
Tb
terbium
158.93
± 0.01
66
Dy
dysprosium
162.50
± 0.01
67
Ho
holmium
164.93
± 0.01
68
Er
erbium
167.26
± 0.01
69
Tm
thulium
168.93
± 0.01
70
Yb
ytterbium
173.05
± 0.02
71
Lu
lutetium
174.97
± 0.01
89
Ac
actinium
[227]
90
Th
thorium
232.04
± 0.01
91
Pa
protactinium
231.04
± 0.01
92
U
uranium
238.03
± 0.01
93
Np
neptunium
[237]
94
Pu
plutonium
[244]
95
Am
americium
[243]
96
Cm
curium
[247]
97
Bk
berkelium
[247]
98
Cf
californium
[251]
99
Es
einsteinium
[252]
100
Fm
fermium
[257]
101
Md
mendelevium
[258]
102
No
nobelium
[259]
103
Lr
lawrencium
[262]
21
Sc
scandium
44.956
± 0.001
39
Y
yttrium
88.906
± 0.001
57-71
lanthanoids
89-103
actinoids
atomic number
Symbol
name
abridged standard
atomic weight
2
13
14
15
16
17
Key:
3
4
5
6
7
8
9
10
11
12
For notes and updates to this table, see www.iupac.org. This version is dated 4 May 2022.
Copyright © 2022 IUPAC, the International Union of Pure and Applied Chemistry.
H – nonmetal
Mg – metal, brittle soft
Mo – metal, brittle hard
Cu – metal, ductile malleable soft
Ti – metal, ductile malleable hard
Tc – synthetic/very rare/unstable
█ – light metal
█ – heavy metal
█ – low-melting metal
█ – refractory metal
█ – noble metal
█ – rare-earth metal
█ – metalloid
See jacobchiu.com for details on this edit by Jacob Chiu.
This version is dated 16 February 2024