Metalloids

Metalloid is a term used in chemistry when classifying the chemical elements. On the basis of their general physical and chemical properties, nearly every element in the periodic table can be termed either a metal or a nonmetal - however a few elements with intermediate properties are referred to as metalloids. (In Greek metallon = metal and eidos = sort).

There is no rigorous definition of the term, however the following properties are usually considered characteristic of metalloids:

metalloids often form amphoteric oxides.
metalloids often behave as semiconductors (B,Si,Ge) to semimetals (eg. Sb).

The concepts of metalloid and semiconductor should not be confused. Metalloid refers to the properties of certain elements in relation to the periodic table. Semiconductor refers to the physical properties of materials (including alloys, compounds) and there is only partial overlap between the two.

The following elements are generally considered metalloids:

Boron (B)
Silicon (Si)
Germanium (Ge)
Arsenic (As)
Antimony (Sb)
Tellurium (Te)
Polonium (Po)
Astatine (At)

Some allotropes of elements exhibit more pronounced metal, metalloid or non-metal behavior than others. For example, for the element carbon, its diamond allotrope is clearly non-metallic, however the graphite allotrope displays limited electric conductivity more characteristic of a metalloid. Phosphorus, tin, selenium and bismuth also have allotropes which display borderline behavior.

In the standard layout of the periodic table, metalloids occur along the diagonal line through the p block from boron to astatine. Elements to the upper right of this line display increasing nonmetallic behaviour; elements to the lower left display increasing metallic behaviour. This line is called the "stair-step" or "staircase." The poor metals are to the left and down and the nonmetals are to the right and up. In addition, the halogens are found at the right.

13	14	15	16	17
B Boron	C Carbon	N Nitrogen	O Oxygen	F Fluorine
Al Aluminium	Si Silicon	P Phosphorus	S Sulfur	Cl Chlorine
Ga Gallium	Ge Germanium	As Arsenic	Se Selenium	Br Bromine
In Indium	Sn Tin	Sb Antimony	Te Tellurium	I Iodine
Tl Thallium	Pb Lead	Bi Bismuth	Po Polonium	At Astatine

Chemical series of the periodic table

	Alkali metals
	Alkaline earth metals
	Lanthanides
	Actinides
	Transition metals

	Poor metals
	Metalloids
	Nonmetals
	Halogens
	Noble gases

The periodic table of the chemical elements is a tabular method of displaying the chemical elements. Although precursors to this table exist, its invention is generally credited to Russian chemist Dmitri Mendeleev in 1869. Mendeleev intended the table to illustrate recurring ('periodic') trends in the properties of the elements. The layout of the table has been refined and extended over time, as new elements have been discovered, and new theoretical models have been developed to explain chemical behavior.

The periodic table is now ubiquitous within the academic discipline of chemistry, providing an extremely useful framework to classify, systematize and compare all the many different forms of chemical behavior. The table has also found wide application in physics, biology, engineering, and industry. The current standard table contains 117 confirmed elements as of October 16, 2006 (while element 118 has been synthesized, element 117 has not).

Navigation

Why join?

Company

SEKOM Handelsges.m.b.H....

Our company is a private firm founded in 1990 with aim to develop export and import with Russia. We do promote EU industrial and consumer goods in Russia and strongly support marketing of Russian and CIS industrial products and services.

0 selling & 0 buying leads

Upcoming events

Human Resources
25 September 2013, Istanbul
Marriott Asia Hotel

Future of Commercial Vehicles
26 September 2013, Istanbul
Marriott Asia Hotel

Steel Today & Tomorrow
5-6 November 2013, Istanbul
Marriott Asia Hotel

Energy in Turkey
4-5 December 2013, Istanbul
Marriott Asia Hotel

Metalloids

Chemical series of the periodic table

Navigation

Company

Upcoming events

Friendly links