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'''Nonmetal''', or '''non-metal''', is a term used in [[chemistry]] when classifying the [[chemical element]]s. 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 [[metalloid]]s.) |
'''Nonmetal''', or '''non-metal''', is a term used in [[chemistry]] when classifying the [[chemical element]]s. 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 [[metalloid]]s.) |
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==See also== |
==See also== |
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*[[Metallic elements]] |
*[[Metallic elements]] |
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*[[Metals]] |
*[[Metals]] |
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==References== |
==References== |
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- Main article: Chemical elements
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
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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