Nonmetal

Nonmetal is a term used in chemistry when classifying the chemical elements. On the basis of their general physical and chemical properties, the element of the periodic table can be classified as metals, nonmetals, and metalloids.

Only 18 elements of the periodic table are generally considered nonmetals, whereas more than 80 elements are considered metals. Nonmetals, however, make up most of the crust, atmosphere, and oceans of the Earth. In addition, bulk tissues of living organisms are composed almost entirely of nonmetals.

List of nonmetals

The elements generally regarded as nonmetals are noted below, along with their groups in the periodic table.

• Group 1: hydrogen (H)
• Group 14: carbon (C)
• Group 15 (the pnictogens): nitrogen (N), phosphorus (P)
• Group 16 (the chalcogens): oxygen (O), sulfur (S), selenium (Se)
• Group 17 (the halogens), all elements: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At)
• Group 18 (the noble gases), all elements: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn)

If one looks at their positions in the periodic table, it is clear that almost all the nonmetals (except for hydrogen) are located on the upper right-hand side of the table. They are separated from metals by the group of elements known as metalloids.

General properties

There is no rigorous definition for the term "nonmetal"—it covers a general spectrum of behavior. The following are some general properties considered characteristic of nonmetals.

• Nonmetals are poor conductors of heat and electricity, whereas metals are relatively good conductors.
• Nonmetals form acidic oxides. By contrast, metals generally form basic oxides.
• In the solid form, nonmetals are dull and brittle. Metals, on the other hand, are generally lustrous, ductile, and malleable.
• Nonmetals usually have lower densities than metals.
• The melting points and boiling points of nonmetals are significantly lower than those of metals.
• Nonmetals have high electronegativity values.
• Most nonmetals tend to gain electrons relatively easily, attracting them away from metals.
• Most nonmetals have high values of ionization energy.

At room temperature, many nonmetals (hydrogen, nitrogen, oxygen, fluorine, chlorine, and the noble gases) are gases; one nonmetal (bromine) is a liquid; the remaining nonmetals are solids. Nonmetals in the gaseous state exist as single atoms or diatomic molecules.

Metallization at extremely high pressures

At extremely high pressures, the nonmetals tend to become metallic in nature.

See also

• Argon
• Astatine
• Bromine
• Carbon
• Chlorine
• Fluorine
• Helium
• Hydrogen
• Iodine
• Krypton
• Metal
• Metalloid
• Neon
• Nitrogen
• Oxygen
• Phosphorus
• Radon
• Selenium
• Sulfur
• Xenon

References

ISBN links support NWE through referral fees

• Brown Jr., Theodore L., H. Eugene LeMay, Bruce Edward Bursten, and Julia R. Burdge. 2002. Chemistry: The Central Science. 9th ed. Upper Saddle River, NJ: Prentice Hall. ISBN 0130669970.

• Chang, Raymond. 2006. Chemistry. 9th ed. New York, NY: McGraw-Hill Science/Engineering/Math. ISBN 0073221031.

• Cotton, F. Albert, and Geoffrey Wilkinson. 1980. Advanced Inorganic Chemistry. 4th ed. New York, NY: Wiley. ISBN 0-471-02775-8.

• Greenwood, N.N., and A. Earnshaw. 1997. Chemistry of the Elements. 2nd ed. Oxford, U.K.; Burlington, MA: Butterworth-Heinemann, Elsevier Science. ISBN 0750633654. Online version available here. Retrieved July 23, 2008.

External links

• Periodic Table: Non-Metals. ChemicalElements.com. Retrieved July 24, 2008.

• Nonmetals. About.com:Chemistry. Retrieved July 24, 2008.

• Non-metal. Encyclopaedia. Retrieved July 24, 2008.

• Non-metal. Encyclopaedia. Retrieved July 24, 2008.

Periodic tables

Standard table | Vertical table | Table with names | Names and atomic masses (large) | Names and atomic masses (small) | Names and atomic masses (text only) | Inline F-block | Elements to 218 | Electron configurations | Metals and non metals | Table by blocks | List of elements by name

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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