Nonmetal is a term used in chemistry when classifying the chemical elements. Chemistry (from Egyptian kēme (chem meaning "earth") is the Science concerned with the composition structure and properties A chemical element is a type of Atom that is distinguished by its Atomic number; that is by the number of Protons in its nucleus. 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. 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 The M acro E xpansion T emplate A ttribute L anguage complements TAL, providing macros which allow the reuse of code across (A few elements with intermediate properties are referred to as 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 )

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 behaviour. Hydrogen (ˈhaɪdrədʒən is the Chemical element with Atomic number 1 Carbon (kɑɹbən is a Chemical element with the symbol C and its Atomic number is 6 Nitrogen (ˈnaɪtɹəʤɪn is a Chemical element that has the symbol N and Atomic number 7 and Atomic weight 14 Phosphorus, (ˈfɒsfərəs is the Chemical element that has the symbol P and Atomic number 15 See also Gold chalcogenides Periodic table Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Sulfur or sulphur (ˈsʌlfɚ see spelling below) is the Chemical element that has the Atomic number 16 Selenium (səˈliniəm is a Chemical element with the Atomic number 34 represented by the chemical symbol Se, an atomic mass of 78 Abundance Owing to their high Reactivity, the halogens are found in the environment only in compounds or as Ions Halide ions and oxoanions History Noble gas is translated from the German noun de ''Edelgas'' first used in 1898 by Hugo Erdmann to indicate their extremely low level of reactivity 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
• nonmetals usually have little or no luster

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. In Physics, heat, symbolized by Q, is Energy transferred from one body or system to another due to a difference in Temperature Electrical conductivity or specific conductivity is a measure of a material's ability to conduct an Electric current. In Computer science, ACID ( Atomicity Consistency Isolation Durability) is a set of properties that guarantee that Database transactions are An oxide is a Chemical compound containing at least one Oxygen atom as well as at least one other element In Chemistry, a base is most commonly thought of as an aqueous substance that can accept Protons This refers to the Brønsted-Lowry theory of acids and Lustre (or luster) is a description of the way light interacts with the surface of a Crystal, rock, or Mineral. Ductility is a mechanical property used to describe the extent to which materials can be deformed plastically or "stretched" into "wires" without For malleability in Cryptography, see Malleability (cryptography. The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different The melting point of a solid is the temperature range at which it changes state from solid to Liquid. The boiling point of a liquid is the temperature at which the Vapor pressure of the liquid equals the environmental pressure surrounding the liquid " Electronegativity " is the opposite of " Electropositivity," which describes an element's ability to donate electrons EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001 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. In Physics and Chemistry, monatomic is a combination of the words "mono" and "atomic" and means "single Atom. Diatomic molecules are molecules made only of two Atoms of either the same or different Chemical elements The prefix di- means two in Greek

Metallisation 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

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