Difference between revisions of "Nonmetal" - New World Encyclopedia

Revision as of 23:58, 23 July 2008

Nonmetal is a term used in chemistry when classifying the chemical elements. On the basis of their general physical and chemical properties, every element in the periodic table can be termed either a metal or a non-metal. (A few elements with intermediate properties are referred to as metalloids.)

The elements generally regarded as nonmetals are:

hydrogen (H)
In Group 14: carbon (C)
In Group 15 (the pnictogens): nitrogen (N), phosphorus (P)
Several elements in Group 16, the chalcogens: oxygen (O), sulfur (S), selenium (Se)
All elements in Group 17 - the halogens
All elements in Group 18 - the noble gases

There is no rigorous definition for the term "nonmetal" - it covers a general spectrum of behavior. Common properties considered characteristic of a nonmetal include:

poor conductors of heat and electricity when compared to metals
they form acidic oxides (whereas metals generally form basic oxides)
in solid form, they are dull and brittle, rather than metals which are lustrous, ductile or malleable
usually have lower densities than metals
they have significantly lower melting points and boiling points than metals
non-metals have high electronegativity

Only eighteen elements in the periodic table are generally considered nonmetals, compared to over eighty metals, but nonmetals make up most of the crust, atmosphere and oceans of the earth. Bulk tissues of living organisms are composed almost entirely of nonmetals. Most nonmetals form monatomic or diatomic molecules in their elemental state, unlike metals which (in their elemental state) do not form molecules at all.

Metallization at huge pressures

Nevertheless, even these 20 elements tend to become metallic at large enough pressures (see nearby periodic table at ~300 GPa).

Notes

References
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External links

Periodic tables

Groups: 1 - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9 - 10 - 11 - 12 - 13 - 14 - 15 - 16 - 17 - 18

Periods: 1 - 2 - 3 - 4 - 5 - 6 - 7 - 8

Series: Alkalis - Alkaline earths - Lanthanides - Actinides - Transition metals - Poor metals - Metalloids - Nonmetals - Halogens - Noble gases

Blocks: s-block - p-block - d-block - f-block - g-block

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@@ Line 10: / Line 10: @@
 <!-- Deleted image removed: [[Image:Nonmetals at 3 million atmospheres.png|thumb|400px|A possible form of periodic table at a pressure of three million atmospheres. It is possible that all the elements become metallic at sufficiently high pressure. The elements C, N, F, Cl, Ne, Ar, Kr, and He (in grey) have not yet been investigated at sufficiently high pressures to achieve metallisation.<ref>{{citejournal|journal=ChemPhysChem|volume=3|issue=1|pages=53 - 56|published=2002-01-14|author=Peter P. Edwards, Friedrich Hensel|title=Metallic Oxygen|publisher=WILEY-VCH-Verlag|location=Weinheim, Germany|year=2002|url=http://www3.interscience.wiley.com/cgi-bin/abstract/89014409/ABSTRACT?CRETRY=1&SRETRY=0|accessdate=2008-01-08}}</ref>]] —>
-There is no rigorous definition for the term "nonmetal" - it covers a general spectrum of behaviour. Common properties considered characteristic of a nonmetal include:
+There is no rigorous definition for the term "nonmetal" - it covers a general spectrum of behavior. Common properties considered characteristic of a nonmetal include:
 * poor conductors of [[heat]] and [[Electrical conductivity|electricity]] when compared to metals
 * they form [[acid]]ic [[oxide]]s (whereas metals generally form [[Base (chemistry)|basic]] oxides)
@@ Line 20: / Line 20: @@
 Only eighteen elements in the periodic table are generally considered nonmetals, compared to over eighty metals, but nonmetals make up most of the crust, atmosphere and oceans of the [[earth]]. Bulk tissues of living [[organism]]s are composed almost entirely of nonmetals. Most nonmetals form [[monatomic]] or [[diatomic molecule]]s in their elemental state, unlike metals which (in their elemental state) do not form molecules at all.
-===Metallisation at huge pressures===
+===Metallization at huge pressures===
 Nevertheless, even these 20 elements tend to become metallic at large enough pressures (see nearby periodic table at ~300 GPa).
 ==See also==
-{{reflist}}
+* [[Argon]]
+* [[Astatine]]
+* [[Bromine]]
+* [[Carbon]]
+* [[Chlorine]]
+* [[Fluorine]]
+* [[Helium]]
+* [[Hydrogen]]
+* [[Krypton]]
+* [[Neon]]
+* [[Nitrogen]]
+* [[Phosphorus]]
+* [[Radon]]
+* [[Xenon]]
+== Notes ==
+<references/>
+== References ==
+== External links ==
 {{PeriodicTablesFooter}}