Non metal is a substance containing finite activation energy (it means band gap) for electron conduction. Non metals have low (insulators) to moderate (semiconductors) bulk electrical conductivities that rise with temperature and are subject to dielectric breakdown at high temperatures and voltages. Like metals, nonmetals can take place in the solid, liquid, or gaseous state. Nonmetals, unlike metals, have a wide variety of mechanical and optical properties, varying from brittle to plastic and invisible to translucent.
There are many examples of non metals such as N, O, NaNO3.
About Non Metals
From the chemical standpoint, nonmetals can be divided into two classes as (1) covalent materials that contain atoms with high electronegativities, small sizes, a pronounced tendency, and low valence vacancy to the electron ratios to form the negative ions in chemical reactions and negative oxidation states in their respective compounds; (2) ionic materials, that have both small and large atoms. Ions can be formed by adding the electrons to (that are the small, electronegative atoms) or by extracting the electrons from (either large or electropositive) atoms.
Nonmetals Occur as Monatomic Anions
(for example, F in NaF) or as constituents of polyatomic anions (for example, N and O in the NO3-s in NaNO3) in ionic materials. When in the simple elemental substance form, up to either 22 or 25% of the well-known elements produce nonmetals at the normal pressures and temperatures, including all of the elements in the periodic table’s S-block and nearly 58% of those in the P-block.
Nonmetals exhibit more variability in their properties than metals do. These properties are largely defined by the molecular structures and interatomic bonding strengths of the nonmetals involved; both are subjected to variation as the valence electron count in every nonmetal varies. In contrast, metals contain more homogenous structures, and their properties are easily reconciled.
Physically, they exist as monatomic or diatomic gases largely, with the remainder containing more substantial (which means the open-packed) forms, unlike metals, which are approximately all solid and close-packed. If a solid has a submetallic appearance (with the exception of sulphur) and is often brittle, as compared to metals, which are lustrous and malleable or ductile, they have smaller densities, are normally lesser conductors of electricity and heat, and have slightly lower melting and boiling points than metals.
From the chemical standpoint, the nonmetals mostly contain high electron affinities (nitrogen and the noble gases contain the negative electron affinities), high ionization energies, and also high electronegativity values (n1), noting that, generally, the higher ionization energy of the element, electronegativity, and electron affinity, the more nonmetallic that the element is.
Nonmetals, including to the limited extent such as probably radon and xenon, usually exist as oxyanions or anions in an aqueous solution; they commonly produce covalent or ionic compounds when combined with the metals (not like metals, which mostly produce the alloys with other metals); and contain acidic oxides, whereas the common oxides of approximately all metals are basic.
Comparison of Properties
Characteristics, including the other properties of reactive nonmetals, metalloids, and noble gases, can be summarized in a tabulated form. Also, metalloids have been included in the light of their nonmetallic chemistry generally. Chemical properties vary from general to particular, and then to descriptive, while physical properties may be described in a loose order for ease of classification.
To the next left of most nonmetals in the periodic table are metalloids such as silicon, germanium, and boron, which generally behave chemically the same as nonmetals and are included for comparative purposes. In this case, they are regarded as the most metallic of the nonmetallic elements.
The seven metalloids are given as Silicon (Si), Boron (B), Arsenic (As), Germanium (Ge), Tellurium (Te), Antimony (Sb), and Astatine (At). On the standard periodic table, they take place in a diagonal area in the p-block, extending from the boron at the top-left to the astatine at a lower right, along with the dividing line between both metals and nonmetals represented on a few periodic tables. They are mainly called metalloids in light of their physical resemblance to metals.
The reactive nonmetals contain a diverse range of individual physical properties and chemical properties. In the periodic table terms, they occupy largely a position between weakly nonmetallic metalloids to the left and noble gases to the right.
We can categorize six noble gases of nonmetals as Neon (Ne), Helium (He), Krypton (Kr), Argon (Ar), the Radioactive Radon (Rn), and the Xenon (Xe). In terms of the periodic table, they occupy the outermost right column, which is called noble gases, in light of their very low chemical reactivity, characteristically.
They contain the most similar properties, all being odourless, colourless, and nonflammable. With their closed valence shells, the noble gases contain feeble interatomic forces of attraction, resulting in low melting points and boiling points. Because of this, they are all the gases under standard conditions, even those with atomic masses, which are larger than several normally solid elements.
Sometimes, for example, the nonmetals, instead, are divided according to the relative homogeneity of halogens, electronegativity, physical form; the peculiar nature of hydrogen; molecular structure; variations thereupon; the corrosive nature of oxygen; halogens.