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(Created page with '{{BioPsy}} '''Nonmetal''', or '''non-metal''', is a term used in chemistry when classifying the chemical elements. On the basis of their general physical and chemical pro…')
 
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* In Group 15(the [[pnictogens]]): [[nitrogen]] (N), [[phosphorus]] (P)
  
* In Group 15(the [[pnictogens]]): [[nitrogen]] (N), [[phosphorus]] (P)
 
* Several elements in Group 16, the [[chalcogens]]: [[oxygen]] (O), [[sulfur]] (S), [[selenium]] (Se)
  
* Several elements in Group 16, the [[chalcogens]]: [[oxygen]] (O), [[sulfur]] (S), [[selenium]] (Se)
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* All elements in Group 17 (Exept for Astatine) - the [[halogen]]s
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* All elements in Group 17 (Exept for Astatine) - the halogens
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* All elements in Group 18 - the [[noble gas]]es
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* All elements in Group 18 - the noble gases
 
<!-- 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>]] -->
  
<!-- 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>]] -->
   
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* poor conductors of [[heat]] and [[Electrical conductivity|electricity]] when compared to metals
  
* 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)
  
* they form [[acid]]ic [[oxide]]s (whereas metals generally form [[Base (chemistry)|basic]] oxides)
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* in solid form, they are dull and [[brittle]], rather than metals which are [[Lustre (mineralogy)|lustrous]], [[ductile]] or [[malleable]]
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* in solid form, they are dull and brittle, rather than metals which are lustrous, ductile or malleable
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* usually have lower [[density|densities]] than metals
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* usually have lower densities than metals
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* they have significantly lower [[melting point]]s and [[boiling point]]s than metals
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* they have significantly lower melting points and boiling points than metals
 
* non-metals have high [[electronegativity]]
  
* non-metals have high [[electronegativity]]
   
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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 are [[monatomic]] noble gases or form [[diatomic molecule]]s in their elemental state, unlike metals which (in their elemental state) do not form molecules at all.
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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 are monatomic noble gases or form diatomic molecules in their elemental state, unlike metals which (in their elemental state) do not form molecules at all.
   
 
==Evolution and the use of nonmetals==
  
==Evolution and the use of nonmetals==

Revision as of 10:01, 21 November 2009

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Nonmetal, or non-metal, 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 nonmetal. (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 (Exept for Astatine) - 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 behaviour. 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 are monatomic noble gases or form diatomic molecules in their elemental state, unlike metals which (in their elemental state) do not form molecules at all.

Evolution and the use of nonmetals

We are carbon life forms that need to breath oxygen.

See also


References


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Periodic tables
Layouts

Standard · Vertical · Full names · Names and atomic masses · Text for last · Huge table · Metals and nonmetals · Blocks · Valences · Inline f-block · 218 elements · Electron configurations · Atomic masses · Electronegativities · Alternatives

Lists of elements

Name · Atomic symbol · Atomic number · Boiling point · Melting point · Density · Atomic mass

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

Template:Compact periodic table

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