Nonmetal Nitrogen Oxygen Phosphorus Sulfur

The poor metals among the BCNOs usually include aluminum, gallium, indium, thallium, tin, lead, and bismuth. The metalloids are boron, silicon, germanium, arsenic, antimony, tellurium, and polonium. The nonmetals are carbon, nitrogen, oxygen, phosphorus, sulfur and selenium. These groups are not official, and chemists sometimes disagree on whether a particular element like boron should be called a metal or a metalloid. 

Many of the nonmetals such as hydrogen, carbon, nitrogen, oxygen, phosphorus, sulfur, chlorine, and iodine are essential elements, and most are used in quantities far beyond the trace levels. Nevertheless, most of the chemistry of these elements in biological systems is more closely associated with organic chemistry than with inorganic chemistry. 

Carbon atoms readily form covalent bonds with other carbon atoms and with atoms of other nonmetals, especially hydrogen, nitrogen, oxygen, phosphorus, sulfur, and the halogens. Carbon atoms form these bonds by sharing pairs of electrons with atoms of other elements. When two atoms share two electrons, the bond is called a single bond (symbolized in a structural formula by a single dash - ). When four electrons are shared, the bond is called a double bond (symbolized by a double dash = ). When six electrons are shared, the bond is called a triple bond (symbolized by a triple dash <=> ). A carbon atom will... 

Carbon, nitrogen, oxygen, phosphorus, and sulfur—a cluster of nonmetals in the periodic table (Figure 5.5)—are extremely important elements. Carbon is important because it is the element upon which all life is based. All organic compounds, which encompasses nearly all 13 million compounds that exist (see Chapter 14), contain carbon. Elemental carbon exists as several different allotropes, or different forms of the same element. These include diamond, graphite, and buckminsterfullerene, which is a form more recently synthesized. Inorganic compounds of carbon are also important. These include... 

Most polyatomic ions consist of a nonmetal such as phosphorus, sulfur, carbon, or nitrogen covalently bonded to oxygen atoms. 

An ionic compound may also contain a polyatomic ion as one of its cations or anions. A polyatomic ion is a group of covalently bonded atoms that has an overall ionic charge. Most polyatomic ions consist of a nonmetal such as phosphorus, sulfur, carbon, or nitrogen covalently bonded to oxygen atoms. 

The octet rule accounts for the valences of many of the elements and the structures of many compounds. Carbon, nitrogen, oxygen, and fluorine obey the octet rule rigorously, provided there are enough electrons to go around. However, some compounds have an odd number of electrons. In addition, an atom of phosphorus, sulfur, chlorine, or another nonmetal in Period 3 and subsequent periods can accommodate more than eight electrons in its valence shell. The following two sections show how to recognize exceptions to the octet rule. 

Nonmetals carbon, nitrogen, oxygen, silicon, phosphorus, sulfur, chlorine, bromine, and iodine... 

The elements of groups 13—16 fall into three categories (Fig. 1.3), the metalloids, the other metals, and the nonmetals. The important biological role of some of the nonmetals, oxygen, nitrogen, phosphorus, sulfur, and selenium together with the halogens, chlorine and iodine, will be discussed in Chapter 18. 

For nonmetals there is no single rule. Carbon, for example, exists as an extensive three-dimensional network of atoms, and so we use its empirical formula (C) to represent elemental carbon in chemical eqnations. Bnt hydrogen, nitrogen, oxygen, and the halogens exist as diatomic molecules, and so we use their molecular formulas (H2, N2, O2, F2, CI2, Br2,12) in equations. The stable form of phosphorus is molecular (P4), and so we use P4. For sulfur chemists often nse the empirical formula (S) in chemical equations, rather than Sg which is the stable form. Thus, instead of writing the equation for the combnstion of sulfur as... 

The relatively small number of elements that appear in the upper righthand corner of the periodic table (to the right of the heavy line in Figures 3.7 and 3.9) are called nonmetals. Nonmetals generally lack those properties that characterize metals and show much more variation in their properties than metals do. Whereas almost all metals are solids at normal temperatures, many nonmetals (such as nitrogen, oxygen, chlorine, and neon) are gaseous, and one (bromine) is a liquid. Several nonmetals (such as carbon, phosphorus, and sulfur) are also solids. 

What are the symbols for the following nonmetal elements that are most often present in compounds studied in organic chemistry carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur. Predict a stable isotope for each of these elements. 

Under everyday conditions some elements, including helium, hydrogen, nitrogen, oxygen, and chlorine, are gases. Only two elements—mercury and bromine—are ordinarily liquids. Most of the elements are solids, and of these most are silvery metals. Two distinguishing properties of metals are that they conduct electric current and have a shiny appearance. A second major class of elements, the nonmetals, do not conduct electricity and are not lustrous. The familiar nonmetals include all the elemental gases, and carbon, sulfur, phosphorus, and iodine, which are solids. 

In the first section of this chapter some of the properties of the elements hydrogen, carbon, nitrogen, phosphorus, arsenic, antimony, bismuth, oxygen, sulfur, selenium, tellurium, fluorine, chlorine, bromine, and iodine are described. The following sections are devoted to some of their compounds with one another, especially the single-bonded normal-valence compounds. Compounds of nonmetals with oxygen are discussed in the following chapter. 

Figure A molecular view of some nonmetals (not to scale). Many nonmetals naturally exist as polyatomic (many-atom) molecules, (a) The noble gases (Group 8A/18) occur as 1-atom formula units. An example is helium, He. (b) Hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, and iodine occur as 2-atom formula units. For example, chlorine is CI2. (c) Phosphorus naturally occurs as 4-atom formula units, (d) Sulfur commonly occurs in 8-atom formula units, (e) One form of carbon consists of 60-atom formula units, commonly referred to as buckyballs. The official name of C q is buckminsterfullerene. 

Many nonmetals are gases at room temperature. These include nitrogen, oxygen, fluorine, and chlorine. One nonmetal, hromine, is a liquid. The solid nonmetals include carhon, phosphorus, selenium, sulfur, and iodine. These solids tend to he brittle rather than malleable and ductile. Some nonmetals are illustrated in Figure 3.4. 

Nonmetals such as hydrogen (H), helium (He), carbon (C), nitrogen (N), phosphorus (P), oxygen (O), sulfur (S), selenium (Se), the column 17 commonly referred to as the halogens and the column 18 named noble or inert gases. 

Iron reacts with nonmetals forming their binary compounds. It combines readily with halogens. Reaction is vigorous with chlorine at moderate temperature. With oxygen, it readily forms iron oxides at moderate temperatures. In a finely divided state, the metal is pyrophoric. Iron combines partially with nitrogen only at elevated temperatures. It reacts with carbon, sulfur, phosphorus, arsenic, and silicon at elevated temperatures in the absence of air, forming their binary compounds. 

Some elements are essential to the composition or function of the body. Since the body is mostly water, hydrogen and oxygen are obviously essential elements. Carbon (C) is a component of all life molecules, including proteins, lipids, and carbohydrates. Nitrogen (N) is in all proteins. The other essential nonmetals are phosphorus (P), sulfur (S), chlorine (Cl), selenium (Se), fluorine (F), and iodine (I). The latter two are among the essential trace elements that are required in only small quantities, particularly as constituents of enzymes or as cofactors (nonprotein species essential for enzyme function). The metals present in macro amounts in the body are sodium (Na), potassium (K), and calcium (Ca). Essential trace elements are chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), copper (Cu), zinc (Zn), magnesium (Mg), molybdenum (Mo), nickel (Ni), and perhaps more elements that have not yet been established as essential. 

The metallic elements are familiar to us all through our everyday lives. From experience we know that metals are shiny, conduct heat and electricity very well (think about electrical wires and pots and pans), can be formed into many different shapes (in other words, they are malleable), and can be drawn into wires (are ductile). The only metal that is not a solid at room temperature is mercury, which exists as a liquid and is often used in thermometers. The nonmetal elements familiar to us include the atmospheric gases nitrogen and oxygen (O). Other important nonmetals, especially for the maintenance of life, are carbon (C), hydrogen (H), sulfur (S), and phosphorus (P). Most nonmetals are either gases or solids at room temperature and have properties opposite those of the metals. 

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