a chemical element (as boron, carbon, or nitrogen) that lacks the characteristics of a metal and that is able to form anions, acidic oxides, acids, and stable compounds with hydrogen is known as non metals.
As far as elements are concerned, a nonmetal is simply an element that does not display the properties of a metal. It is not defined by what it is, but by what it is not. It doesn't look metallic, can't be drawn into a wire or pounded into shape or bent, doesn't conduct heat or electricity well, and doesn't have a high melting or boiling point.
The nonmetals are in the minority on the periodic table, mostly pushed to the right hand side of the periodic table. The exception is hydrogen, which behaves as a nonmetal at room temperature and pressure and is found on the upper left corner of the periodic table. Here's a look at which elements are nonmetals, how to locate the nonmetals on the table, and their common properties.Nonmetals have open structures (unless solidified from gaseous or liquid forms); tend to gain or share electrons when they react with other substances; and do not form distinctly basic oxides.
Most are gases at room temperature; have relatively low densities; are poor electrical and thermal conductors; have relatively high ionisation energies and electronegativities; form acidic oxides; and are found naturally in uncombined states in large amounts.
Some nonmetals (C, black P, S and Se) are brittle solids at room temperature (although each of these also have malleable, pliable or ductile allotropes).
From left to right in the periodic table, the nonmetals can be subdivided into thepolyatomic nonmetals which, being nearest to the metalloids, show some incipient metallic character; the diatomic nonmetals, which are essentially nonmetallic; and the monatomic noble gases, which are almost completely inert.
Location on the Nonmetals on the Periodic Table
The nonmetals are located on the upper right side of the periodic table. Nonmetals are separated from metals by a line that cuts diagonally through the region of the periodic table containing elements with partially filled p orbitals
The halogens and noble gases are nonmetals, but the nonmetal element groupusually is considered to consist of the following elements:
- hydrogen
- carbon
- nitrogen
- oxygen
- phosphorus
- sulfur
- selenium
The halogen elements are:
- fluorine
- chlorine
- bromine
- iodine
- astatine
- Possibly element 117, although most scientists think this element will behave as a metalloid.
The noble gas elements are:
- helium
- neon
- argon
- krypton
- xenon
- radon
- element 118
Summary of Common Properties
- High ionization energies
- High electronegativities
- Poor thermal conductors
- Poor electrical conductors
- Brittle solids - not malleable or ductile
- Little or no metallic luster
- Gain electrons easily
- Dull, not metallic-shiny, although they may be colorful
- Lower melting points and boiling point than the metals
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