Periodic Table of the Elements

* Systematic names are used for reported elements until an official name has been accepted.

Atomic masses are averages based upon the naturally occurring composition of isotopes on Earth. For elements that have slightly different isotopic composition depending on the source, IUPAC now reports a range of values for atomic masses. These atomic masses are shown here in bold italics. The atomic masses in this table have been rounded to values sufficiently accurate for everyday calculations. Per IUPAC convention, no values are listed for elements whose isotopes lack a characteristic abundance in natural samples.

The discoveries of elements with atomic numbers 113, 115, and 117 -118 have been reported but not fully confirmed.

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13
Al
Aluminum
26.981 5386
Group 1
1
H
Hydrogen
1.007 94
2
He
Helium
4.002 602
3
Li
Lithium
6.941
4
Be
Beryllium
9.012 182
5
B
Boron
10.811
6
C
Carbon
12.0107
7
N
Nitrogen
14.0067
8
O
Oxygen
15.9994
9
F
Fluorine
18.998 4032
10
Ne
Neon
20.1797
11
Na
Sodium
22.989 769 28
12
Mg
Magnesium
24.3050
13
Al
Aluminum
26.981 5386
14
Si
Silicon
28.0855
15
P
Phosphorus
30.973 762
16
S
Sulfur
32.065
17
Cl
Chlorine
35.453
18
Ar
Argon
39.948
19
K
Potassium
39.0983
20
Ca
Calcium
40.078
21
Sc
Scandium
44.955 912
22
Ti
Titanium
47.867
23
V
Vanadium
50.9415
24
Cr
Chromium
51.9961
25
Mn
Manganese
54.938 045
26
Fe
Iron
55.845
27
Co
Cobalt
58.933 195
28
Ni
Nickel
58.6934
29
Cu
Copper
63.546
30
Zn
Zinc
65.38
31
Ga
Gallium
69.723
32
Ge
Germanium
72.64
33
As
Arsenic
74.921 60
34
Se
Selenium
78.96
35
Br
Bromine
79.904
36
Kr
Krypton
83.798
37
Rb
Rubidium
85.4678
38
Sr
Strontium
87.62
39
Y
Yttrium
88.905 85
40
Zr
Zirconium
91.224
41
Nb
Niobium
92.906 38
42
Mo
Molybdenum
95.96
43
Tc
Technetium
(98)
44
Ru
Ruthenium
101.07
45
Rh
Rhodium
102.905 50
46
Pd
Palladium
106.42
47
Ag
Silver
107.8682
48
Cd
Cadmium
112.411
49
In
Indium
114.818
50
Sn
Tin
118.710
51
Sb
Antimony
121.760
52
Te
Tellurium
127.60
53
I
Iodine
126.904 47
54
Xe
Xenon
131.293
55
Cs
Cesium
132.905 4519
56
Ba
Barium
137.327
57
La
Lanthanum
138.905 47
58
Ce
Cerium
140.116
59
Pr
Praseodymium
140.907 65
60
Nd
Neodymium
144.242
61
Pm
Promethium
(145)
62
Sm
Samarium
150.36
63
Eu
Europium
151.964
64
Gd
Gadolinium
157.25
65
Tb
Terbium
158.925 35
66
Dy
Dysprosium
162.500
67
Ho
Holmium
164.930 32
68
Er
Erbium
167.259
69
Tm
Thulium
168.934 21
70
Yb
Ytterbium
173.054
71
Lu
Lutetium
174.9668
72
Hf
Hafnium
178.49
73
Ta
Tantalum
180.947 88
74
W
Tungsten
183.84
75
Re
Rhenium
186.207
76
Os
Osmium
190.23
77
Ir
Iridium
192.217
78
Pt
Platinum
195.084
79
Au
Gold
196.966 569
80
Hg
Mercury
200.59
81
Tl
Thallium
204.3833
82
Pb
Lead
207.2
83
Bi
Bismuth
208.980 40
84
Po
Polonium
(209)
85
At
Astatine
(210)
86
Rn
Radon
(222)
87
Fr
Francium
(223)
88
Ra
Radium
(226)
89
Ac
Actinium
(227)
90
Th
Thorium
232.038 06
91
Pa
Protactinium
231.035 88
92
U
Uranium
238.028 91
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)
104
Rf
Rutherfordium
(261)
105
Db
Dubnium
(262)
106
Sg
Seaborgium
(266)
107
Bh
Bohrium
(264)
108
Hs
Hassium
(277)
109
Mt
Meitnerium
(268)
110
Ds
Darmstadtium
(271)
111
Rg
Roentgenium
(272)
112
Cn
Copernicium
(285)
113
Uut*
Ununtrium
(284)
114
FL
Flerovium
(289)
115
Uup*
Ununpentium
(288)
116
Lv
Livermorium
(292)
117
Uus
Ununseptium
(292)
118
Uuo*
Ununoctium
(294)