Periodic Table

WebElements chemistry nexus

OK - started reorganisation of one WebElements area, the "chemistry nexus". The nexus will now bring together news, articles, the WebElements blog, and eventually the Webelements bibliography, and more. It will also contain chemistry content related to WebElements, for instance, sections on the chemistry of the various groups or periods in the periodic table, articles on periodicity, expanded disucssion of the chemistry of specific elements, and so on. All that will take years to add of course. The existing forums site will be located in a dedicated area at the WebElements chemistry forum.

Scerri: periodic table book

Scerri: periodic table book

The Periodic Table: Its Story and Its Significance by Eric Scerri

Periods in the periodic table

Periods in the periodic table

There are 7 periods in the standard form of the periodic table:

  • Period 1
  • Period 2
  • Period 3
  • Period 4
  • Period 5
  • Period 6
  • Period 7

Period Number

In the standard form of the periodic table the s-block, p-block, and d-block elements are organised into horizontal rows called periods. In WebElements these are labelled from 1 to 7.

The f-block

The f-block elements are assigned to Periods 6 (lanthanoids) and 7 (actinoids) since that is where they are located in the full, or extended, version of the periodic table.

Mendeleev's periodic table

The Mendeleev Periodic Table

This table shows the form of Mendeleev's Periodic Table of the chemical elements as published in 1872. The heading "Reihen" means "Row" and the heading "Gruppe" means "Group". The symbols R2O and RH4, etc., are written in the style of the time which uses superscripts to denote the number of atoms in molecules rather than the current style which uses subscripts. The gaps marked with hyphens ("-") represent chemical elements deduced by Mendeleev as existing but unknown in 1872. He was able to predict with considerable success the properties of some of the missing chemical elements such as germanium.

Reihen Gruppe I.
-
R2O
Gruppe II.
-
RO
Gruppe III.
-
R2O3
Gruppe IV.
RH4
RO2
Gruppe V.
RH3
R2O5
Gruppe VI.
RH2
RO3
Gruppe VII.
RH
R2O7
Gruppe VIII.
-
RO4
1 H=1
2 Li=7 Be=9,4 B=11 C=12 N=14 O=16 F=19
3 Na=23 Mg=24 Al=27,3 Si=28 P=31 S=32 Cl=35,5
4 K=39 Ca=40 -=44 Ti=48 V=51 Cr=52 Mn=55 Fe=56, Ce=59,
Ni=59, Cu=63.
5 (Cu=63) Zn=65 -=68 -=72 As=75 Se=78 Br=80
6 Rb=85 Sr=87 ?Yt=88 Zr=90 Nb=94 Mo=96 -=100 Ru=104, Rh=104,
Pd=106, Ag=108.
7 (Ag=108) Cd=112 In=113 Sn=118 Sb=122 Te=125 J=127
8 Cs=133 Ba=137 ?Di=138 ?Ce=140 - - - - - - -
9 (-) - - - - - -
10 - - ?Er=178 ?La=180 Ta=182 W=184 - Os=195, Ir=197,
Pt=198, Au=199
11 (Au=199) Hg=200 Tl=204 Pb=207 Bi=208 - -
12 - - - Th=231 - U=240 - - - - -

Help pages

Help with WebElementsTM

Reset WebElements Select this icon wherever you see it to go to the home page, either for WebElements or for the current selection in WebElements.
Periodic Table Whenever you see this icon you can select it to show the periodic table. From there, you can use the full periodic table to select any element of interest to you. In practice, you will need to use this link frequently in order to navigate around the table.
The navigation panel to the left always contains a navigation menu. The only exception is when you are viewing the periodic table itself. For each element, this menu will contain some 25 or so categories of information. Use the menu to select whatever is of interest to you.
Once you are reading the data of interest to you, you can navigate between elements in two ways. First, use the periodic table icon link (as above) to switch element. Second, you can navigate to adjacent elements in the periodic table from the table of links shown at the top of each information screen.
speak welcome Whenever you see this icon on the menu for an element, select it to hear the name of the element in more-or-less standard English (provided your computer is equipped for sound).
  There are many other features built in to WebElementsTM, but I'll leave them for you to find.

The Positions of Lanthanum (Actinium] and Lutetium (Lawrencium] in the Periodic Table

The positions of the elements La, Ac, Lu, and Lr in the WebElements periodic table is justified eloquently in the article by William B. Jensen.1 in J. Chem. Ed..

Elements 117 is not known at the time of writing, but are shown "greyed-out" in the tables at their expected positions for information.

Janet periodic table

The Janet periodic table

The Janet periodic table is an excellent alternative periodic table and organises elements according to orbital filling. Therefore, hydrogen is above lithium on the grounds they are both ns1, and helium above beryllium on the grounds they are both ns2. Current Group numbers are displayed to help orientation with the standard table.

The JANET periodic table.
Group   3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 1 2
Period
1 1
H
2
He
1 3
Li
4
Be
2 5
B
6
C
7
N
8
O
9
F
10
Ne
11
Na
12
Mg
3 13
Al
14
Si
15
P
16
S
17
Cl
18
Ar
19
K
20
Ca
4 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
5 39
Y
40
Zr
41
Nb
42
Mo
43
Tc
44
Ru
45
Rh
46
Pd
47
Ag
48
Cd
49
In
50
Sn
51
Sb
52
Te
53
I
54
Xe
55
Cs
56
Ba
6 57
La
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
7 89
Ac
90
Th
91
Pa
92
U
93
Np
94
Pu
95
Am
96
Cm
97
Bk
98
Cf
99
Es
100
Fm
101
Md
102
No
103
Lr
104
Rf
105
Db
106
Sg
107
Bh
108
Hs
109
Mt
110
Ds
111
Rg
112
Cp
113
Uut
114
Uuq
115
Uup
116
Uuh
117
Uus
118
Uuo
119
Uue
120
Ubn

WebElements: the periodic table on the WWW [http://www.webelements.com/]

Copyright 1993-2011 Mark Winter [The University of Sheffield and WebElements Ltd, UK]. All rights reserved.