1. Education

Periodic Table of the Elements

Element Chemical & Physical Properties

This is an online interactive periodic table of the elements. Click on an element symbol in the periodic table to get facts for that element. Printable periodic tables and a list of elements by increasing atomic number are also available.
1
IA
1A
                                18
VIIIA
8A
1
H
1.008
2
IIA
2A
                    13
IIIA
3A
14
IVA
4A
15
VA
5A
16
VIA
6A
17
VIIA
7A
2
He
4.003
3
Li
6.941
4
Be
9.012
                    5
B
10.81
6
C
12.01
7
N
14.01
8
O
16.00
9
F
19.00
10
Ne
20.18
11
Na
22.99
12
Mg
24.31
3
IIIB
3B
4
IVB
4B
5
VB
5B
6
VIB
6B
7
VIIB
7B
8

9
VIII
8
10

11
IB
1B
12
IIB
2B
13
Al
26.98
14
Si
28.09
15
P
30.97
16
S
32.07
17
Cl
35.45
18
Ar
39.95
19
K
39.10
20
Ca
40.08
21
Sc
44.96
22
Ti
47.88
23
V
50.94
24
Cr
52.00
25
Mn
54.94
26
Fe
55.85
27
Co
58.47
28
Ni
58.69
29
Cu
63.55
30
Zn
65.39
31
Ga
69.72
32
Ge
72.59
33
As
74.92
34
Se
78.96
35
Br
79.90
36
Kr
83.80
37
Rb
85.47
38
Sr
87.62
39
Y
88.91
40
Zr
91.22
41
Nb
92.91
42
Mo
95.94
43
Tc
(98)
44
Ru
101.1
45
Rh
102.9
46
Pd
106.4
47
Ag
107.9
48
Cd
112.4
49
In
114.8
50
Sn
118.7
51
Sb
121.8
52
Te
127.6
53
I
126.9
54
Xe
131.3
55
Cs
132.9
56
Ba
137.3
* 72
Hf
178.5
73
Ta
180.9
74
W
183.9
75
Re
186.2
76
Os
190.2
77
Ir
190.2
78
Pt
195.1
79
Au
197.0
80
Hg
200.5
81
Tl
204.4
82
Pb
207.2
83
Bi
209.0
84
Po
(210)
85
At
(210)
86
Rn
(222)
87
Fr
(223)
88
Ra
(226)
** 104
Rf
(257)
105
Db
(260)
106
Sg
(263)
107
Bh
(265)
108
Hs
(265)
109
Mt
(266)
110
Ds
(271)
111
Rg
(272)
112
Cn
(277)
113
Uut
--
114
Fl
(296)
115
Uup
--
116
Lv
(298)
117
Uus
--
118
Uuo
--

*
Lanthanide
Series
57
La
138.9
58
Ce
140.1
59
Pr
140.9
60
Nd
144.2
61
Pm
(147)
62
Sm
150.4
63
Eu
152.0
64
Gd
157.3
65
Tb
158.9
66
Dy
162.5
67
Ho
164.9
68
Er
167.3
69
Tm
168.9
70
Yb
173.0
71
Lu
175.0
**
Actinide
Series
89
Ac
(227)
90
Th
232.0
91
Pa
(231)
92
U
(238)
93
Np
(237)
94
Pu
(242)
95
Am
(243)
96
Cm
(247)
97
Bk
(247)
98
Cf
(249)
99
Es
(254)
100
Fm
(253)
101
Md
(256)
102
No
(254)
103
Lr
(257)

Alkali
Metal
Alkaline
Earth
Semi-Metal Halogen Noble
Gas
Non Metal Basic Metal Transition
Metal
Lanthanide Actinide

More Periodic Table Information

Introduction to the Periodic Table

People have known about elements like carbon and gold since ancient time. The elements couldn't be changed using any chemical method. If you examine samples of iron and silver, you can't tell how many protons the atoms have. However, you can tell the elements apart because they have different properties. You might notice there are more similarities between iron and silver than between iron and oxygen. This is where the periodic table becomes useful. It organizes elements according to trends so that you can see the relationships between them.

What is the Periodic Table?

Dmitri Mendeleev was the first scientist to create a periodic table of the elements similar to the one we use today. You can see Mendeleev's original table (1869). This table showed that when the elements were ordered by increasing atomic weight, a pattern appeared where properties of the elements repeated periodically. This periodic table is a chart that groups the elements according to their similar properties. Mendeleev's table didn't have many elements. He had question marks and spaces between elements where he predicted undiscovered elements would fit.

Why was the Periodic Table Created?

Many elements remained to be discovered in Mendeleev's time. The periodic table helped predict the properties of new elements. The modern periodic table is used to predict properties and reactions of the elements.

Discovering Elements

The number of protons determines the atomic number of an element, which is its number on the periodic table. There aren't any skipped atomic numbers on the modern periodic table because new elements are synthesized rather than discovered. The placement of these new elements on the periodic table can be used to help predict the element's properties.

Element Properties and Trends

The periodic table helps predict some properties of the elements compared to each other. Atom size decreases as you move from left to right across the table and increases as you move down a column. Energy required to remove an electron from an atom increases as you move from left to right and decreases as you move down a column. The ability to   form a chemical bond increases as you move from left to right and decreases as you move down a column.

Today's Periodic Table

The most important difference between Mendeleev's table and today's table is the modern table is organized by increasing atomic number, not increasing atomic weight. Why was the table changed? In 1914, Henry Moseley learned you could experimentally determine the atomic numbers of elements. Before that, atomic numbers were just the order of elements based on increasing atomic weight. Once atomic numbers had significance, the periodic table was reorganized.

Periods and Groups

Elements in the periodic table are arranged in periods (rows) and groups (columns). Atomic number increases as you move across a row or period.

Periods

Rows of elements are called periods. The period number of an element signifies the highest unexcited energy level for an electron in that element. The number of elements in a period increases as you move down the periodic table because there are more sublevels per level as the energy level of the atom increases.

Groups

Columns of elements help define element groups. Elements within a group share several common properties. Groups are elements have the same outer electron arrangement. The outer electrons are called valence electrons. Because they have the same number of valence electrons, elements in a group share similar chemical properties. The Roman numerals listed above each group are the usual number of valence electrons. For example, a group VA element will have 5 valence electrons.

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