WebElementsThe periodic table of the elements
The periodic table is an arrangment of the chemical elements ordered by atomic number so that periodic properties of the elements (chemical periodicity) are made clear.
| Group | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Period 1 |
1
1.008
|
2
4.0026
|
|||||||||||||||||
| 2 |
3
6.94
|
4
9.0122
|
5
10.81
|
6
12.011
|
7
14.007
|
8
15.999
|
9
18.998
|
10
20.180
|
|||||||||||
| 3 |
11
22.990
|
12
24.305
|
13
26.982
|
14
28.085
|
15
30.974
|
16
32.06
|
17
35.45
|
18
39.948
|
|||||||||||
| 4 |
19
39.098
|
20
40.078
|
21
44.956
|
22
47.867
|
23
50.942
|
24
51.996
|
25
54.938
|
26
55.845
|
27
58.933
|
28
58.693
|
29
63.546
|
30
65.38
|
31
69.723
|
32
72.630
|
33
74.922
|
34
78.971
|
35
79.904
|
36
83.798
|
|
| 5 |
37
85.468
|
38
87.62
|
39
88.906
|
40
91.224
|
41
92.906
|
42
95.95
|
43
[98.906]
|
44
101.07
|
45
102.91
|
46
106.42
|
47
107.87
|
48
112.41
|
49
114.82
|
50
118.71
|
51
121.76
|
52
127.60
|
53
126.90
|
54
131.29
|
|
| 6 |
55
132.91
|
56
137.33
|
* |
71
174.97
|
72
178.49
|
73
180.95
|
74
183.84
|
75
186.21
|
76
190.23
|
77
192.22
|
78
195.08
|
79
196.97
|
80
200.59
|
81
204.38
|
82
207.2
|
83
208.98
|
84
[208.98]
|
85
[209.99]
|
86
[222.02]
|
| 7 |
87
[223.02]
|
88
[226.03]
|
** |
103
[262.11]
|
104
[267.12]
|
105
[270.13]
|
106
[269.13]
|
107
[270.13]
|
108
[269.13]
|
109
[278.16]
|
110
[281.17]
|
111
[281.17]
|
112
[285.18]
|
113
[286.18]
|
114
[289.19]
|
115
[289.19]
|
116
[293.20]
|
117
[293.21]
|
118
[294.21]
|
| *Lanthanoids | * |
57
138.91
|
58
140.12
|
59
140.91
|
60
144.24
|
61
[144.91]
|
62
150.36
|
63
151.96
|
64
157.25
|
65
158.93
|
66
162.50
|
67
164.93
|
68
167.26
|
69
168.93
|
70
173.05
|
||||
| **Actinoids | ** |
89
[227.03]
|
90
232.04
|
91
231.04
|
92
238.03
|
93
[237.05]
|
94
[244.06]
|
95
[243.06]
|
96
[247.07]
|
97
[247.07]
|
98
[251.08]
|
99
[252.08]
|
100
[257.10]
|
101
[258.10]
|
102
[259.10]
|
||||
The standard form of the periodic table shown here includes periods (shown horizontally) and groups (shown vertically). The properties of elements in groups are similar in some respects to each other.
There is no one single or best structure for the periodic table but by whatever consensus there is, the form used here is very useful and the most common. The periodic table is a masterpiece of organised chemical information and the evolution of chemistry's periodic table into the current form is an astonishing achievement.