Home > Nonmetal
Together with the metals and metalloids, a nonmetal is one of three categories of chemical elements as distinguished by ionization and bonding properties. These properties stem from the fact that nonmetals are highly electronegative, i.e. they gain valence electrons from other atoms more readily than they give them up.The nonmetals are, in order of atomic number:
- hydrogen (H)
- carbon (C)
- nitrogen (N)
- oxygen (O)
- fluorine (F)
- phosphorus (P)
- sulfur (S)
- chlorineChlorine (from Gr. Chloros meaning "pale green"), is the chemical element with atomic number 17 and symbol Cl . It is a halogen, found in the periodic table in group 17. Chlorine gas is greenish yellow, is two and one half times as heavy as air, has an in (Cl)
- seleniumSelenium is a chemical element in the periodic table that has the symbol Se and atomic number 34. This is a toxic nonmetal that is chemically related to sulfur and tellurium. It occurs in several different forms but one of these is a stable gray metallike (Se)
- bromineBromine (from Gr. Bromos meaning "stench"), is a chemical element in the periodic table that has the symbol Br and atomic number 35. A halogen element, bromine is a red volatile liquid at room temperature which has a reactivity between chlorine and iodine (Br)
- iodineIodine (from the Gr. Iodes meaning "violet"), is a chemical element in the periodic table that has the symbol I and atomic number 53. This is an insoluble element that is required as a trace element for living organisms. Chemically, iodine is the least re (I)
- astatineAstatine is a chemical element in the periodic table that has the symbol At and atomic number 85. This radioactive element occurs naturally from uranium and thorium decay and is the heaviest of the halogens. Notable characteristics This highly radioactive (At)
Most nonmetals are found at the upper right of the periodic tableThe periodic table of the chemical elements is a tabular display of the known chemical elements. The elements are arranged by electron structure so that many chemical properties vary regularly across the table. Each element is listed by its atomic number. The exception is hydrogen, which is usually placed at the upper left with the alkali metalThe alkali metals are a chemical series. They are the elements in Group 1 of the Periodic Table, excluding hydrogen: that is, lithium, sodium, potassium, rubidium, caesium and francium. They are all highly reactive. The alkali metals are silvery colored,s, but behaves like a nonmetal under most conditions. Unlike metals, which are electrically conductive, a nonmetal may be an insulatorInsulators are materials which prevent the flow of heat (thermal insulators) or electrical current (electrical insulators). The opposite of electrical insulators are conductors and semiconductors, which permit the flow of current (Note: a semiconductor is or a semiconductor. Nonmetals may form ionic bonds with metals by gaining electrons, or covalent bonds with other nonmetals. The oxides of nonmetals are acidic.
There are only twelve known nonmetals, compared to over eighty metals, but nonmetals make up most of the earth, particularly in the outer layers. Organisms are composed almost entirely of nonmetals. Many nonmetals (hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, and iodine) are diatomic, and most of the rest are otherwise polyatomic.
Chemical element groups
