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Metalloids in the Periodic Table

Metalloids in the Periodic Table

Metalloids are elements from the periodic table with properties that lie between metals and non-metals. The following ScienceStruck article will cover some information related to metalloids.
Batul Nafisa Baxamusa
The first person to come up with a periodic table of elements was Dmitri Ivanovich Mendeleev, a Russian chemist. He came up with the first version of periodic table in 1864. Mendeleev's table was based on the atomic weight of the elements. He found that there were many elements that shared similar properties and occurred periodically. Thus, he came up with the concept of periodic table of elements. His table had been divided into three main sections - metals, nonmetals, and metalloids. In this article, we shall concentrate on the metalloids from the periodic table.

Classification of Periodic Table

According to Mendeleev's law of periodic table, the chemical and physical properties of elements vary in a periodic fashion according to their atomic weights. However, the modern periodic table of elements follow the law that, the properties of elements vary according to their atomic number and not by their weight. The elements of a Mendeleev's table were arranged in rows called periods and columns called groups. The chemical elements of the same group had similar properties. There are different regions in the periodic table that are called periodic table blocks, as they are named according to the subshell of the last electron of the atom.

Location of Metalloids in the Periodic Table

The metalloids, also known as semi-metals, are placed between metals and non-metals in the periodic table of elements. There are seven elements that are classified as metalloids and placed in Group 13, 14, 15, 16, and 17. They are found in a stair step line that helps differentiate metals from non-metals in this element table. The line that separates metalloids from the metals and non-metals in the periodic table is called amphoteric line.

List of Metalloid Elements

As mentioned above, there are 7 elements in the periodic table that exhibit metalloid behavior. They occur in a diagonal line from boron to astatine through the p-block. The elements in the upper-right portion of the line show increasing non-metallic behavior and the elements at the lower-left of the line show increasing metallic behavior. The list of metalloids in the periodic table are as follows:
  • Boron (B)
  • Silicon (Si)
  • Germanium (Ge)
  • Arsenic (As)
  • Antimony (Sb)
  • Tellurium (Te)
  • Polonium (Po)
Metalloids in the Periodic Table

s-blockTransition Elements
d- block
p-blockNobel
Element
Group123456789101112131415161718
1 1
H
1.0079
2
He
4.0026
2 3
Li
6.941
4
Be
9.0122
5
B
10.811
6
C
12.011
7
N
14.007
8
O
15.999
9
F
18.998
10
Ne
20.180
3 11
Na
22.990
12
Mg
24.305
13
Al
26.982
14
Si
28.086
15
P
30.974
16
S
32.066
17
Cl
35.453
18
Ar
39.948
4 19
K
39.098
20
Ca
40.078
21
Sc
44.956
22
Ti
47.867
23
V
50.942
24
Cr
51.996
25
Mn
54.938
26
Fe
55.845
27
Co
58.933
28
Ni
58.693
29
Cu
63.546
30
Zn
65.409
31
Ga
69.723
32
Ge
72.64
33
As
74.922
34
Se
78.96
35
Br
79.904
36
Kr
83.798
5 37
Rb
85.468
38
Sr
87.62
39
Y
88.906
40
Zr
91.224
41
Nb
92.906
42
Mo
95.94
43
Tc
(98)
44
Ru
101.07
45
Rh
102.91
46
Pd
106.42
47
Ag
107.87
48
Cd
112.41
49
In
114.82
50
Sn
118.71
51
Sb
121.76
52
Te
127.60
53
I
126.90
54
Xe
131.29
6 55
Cs
132.91
56
Ba
137.33
57 - 71
La-Lu
72
Hf
178.49
73
Ta
180.95
74
W
183.84
75
Re
186.21
76
Os
190.23
77
Ir
192.22
78
Pt
195.08
79
Au
196.97
80
Hg
200.59
81
Tl
204.38
82
Pb
207.2
83
Bi
208.98
84
Po
(209)
85
At
(210)
86
Rn
(222)
7 87
Fr
(223)
88
Ra
(226)
89 -103
Ac-Lr

104
Rf
(261)
105
Db
(262)
106
Sg
(266)
107
Bh
(264)
108
Hs
(277)
109
Mt
(268)
110
Ds
(281)
111
Rg
(272)
112
Cn
(277)
Lanthanide 57
La
138.91
58
Ce
140.12
59
Pr
140.91
60
Nd
144.24
61
Pm
(145)
62
Sm
150.36
63
Eu
151.96
64
Gd
157.25
65
Tb
158.93
66
Dy
162.50
67
Ho
164.93
68
Er
167.26
69
Tm
168.93
70
Yb
173.04
71
Lu
174.97
Actinide 89
Ac
(227)
90
Th
232.04
91
Pa
231.04
92
U
238.03
93
Np
(237)
94
Pu
(244)
95
Am
(243)
96
Cm
(247)
97
Bk
(247)
98
Cf
(251)
99
Es
(252)
100
Fm
(257)
101
Md
(258)
102
No
(259)
103
Lr
(262)

Key for the Periodic Table

Alkali Metals
Alkaline Earth Metals
Lanthinides
Actinides
Transition Metals
Poor Metals
Other Metals
Nobel Gases
Metalloids
Unknown Chemical Properties

Properties of Metalloids

The term metalloid comes from the Greek word metallon, which means 'metal', and edios, meaning 'sort.' The metalloids are often seen forming amphoteric oxides, and they behave as semiconductors. They have properties of both metals and non-metals in the periodic table. They even carry electric charge that makes them suitable for use in computers and calculators. Their ionization energy as well as electronegativity values are between those of metals and non-metals. Their reactivity depends on the metals that they are reacting with.

As you can see in the periodic table, there is a line that distinguishes boron and aluminum to the border seen between polonium and astatine. However, aluminum is classified under 'other metals'. The element carbon is a non-metal, but graphite displays limited conductivity, which is the characteristic of a metalloid. Silicon and germanium exhibit properties of a semiconductor. When boron reacts with sodium, it acts as a non-metal, whereas in case of reaction with fluorine, boron exhibits metallic properties.