Examples oxidation number

You can also monitor changes in oxidation numbers in reactions that involve covalent molecules. For example, oxidation number changes occur in the reaction of hydrogen and oxygen to form water. 

Functional group Example Oxidation number of carbon in the example... 

Combustion of alkanes is an example of oxidation-reduction Although It IS possible to calculate oxidation numbers of carbon m organic mole cules It IS more convenient to regard oxidation of an organic substance as an increase m its oxygen content or a decrease m its hydrogen content... 

Use of the oxidation number and charge number extends the range for radicals for example, uranyl(VI) or uranyl(2+) cation UOJ, uranyl(V) or uranyl(l+) cation. 

When the characteristic element is partially or wholly present in a lower oxidation state than corresponds to its Periodic Group number, oxidation numbers are used for example, [O2HP—O—P03H] , dihydrogendiphosphate(III,V)(2—). 

The Stock Oxidation-Number System. Stock sought to correct many nomenclature difficulties by introducing Roman numerals in parentheses to indicate the state(s) of oxidation, eg, titanium(II) chloride for TiCl2, iron(II) oxide for FeO, titanium(III) chloride for TiCl, iron(III) oxide for Fe203, titanium(IV) chloride for TiCl, and iron(II,III) oxide for Fe O. In this system, only the termination -ate is used for anions, followed by Roman numerals in parentheses. Examples are potassium manganate(IV) for K2Mn02, potassium tetrachloroplatinate(II) for K PtCl, and sodium hexacyanoferrate(III) for Na3Fe(CN)3. Thus a set of prefixes and terminations becomes uimecessary. 

Many newer poly(phenylene oxide)s have been reported ia the early 1990s. Eor example, a number of poly(2,6-diphenyl-l,4-phenylene oxide)s were prepared with substituents ia the 4-positions of the pendent phenyl groups. Of particular iaterest is the 4-fluoro substitueat, which imparts a lower melting poiat, enhanced solubiUty, and a lesser tendency to crystallize than has been found for the parent material (1). 

The sum of the oxidation numbers in a neutral species is 0 in a polyatomic ion, it is equal to the charge of that ion. The application of this very useful principle is illustrated in Example 4.8. 

As you can deduce from the preceding examples, the oxidation number of the central metal ion is indicated by a Roman numeral written at the end of the name. 

In reaction (19) the iodine shown on the left has an oxidation number of zero. After the reaction, some of the iodine atoms have oxidation number +5 and some —1. In other words, the iodine oxidation number has gone both up and down in the reaction. This is an example of selfoxidation-reduction, sometimes called disproportionation. It is a reaction quite typical of, but not at all restricted to, the halogens. 

When several oxidation numbers are found for the same element, they often differ from each other by jumps of one unit. For example, in the case of vanadium the common oxidation numbers form a continuous series from +2 to +3 to +4 to 4-5. Compare this with the halogens (Chapter 19). In the case of chlorine, for example, the common states are —1, +1, 4-3, 4-5, and 4-7 (jumps of two units instead of one unit). 

The oxidation number of an element in a monatomic ion is the same as its charge. For example, the oxidation number of magnesium is +2 when it is present as Mg2+ ions, and the oxidation number of chlorine is — 1 when it is present as Cl" ions. The oxidation number of the elemental form of an element is 0 so magnesium metal has oxidation number 0 and chlorine in the form of Cl2 molecules also has oxidation number 0. When magnesium combines with chlorine, the oxidation numbers change as follows ... 

EXAMPLE K.l Sample exercise Assigning oxidation numbers... 

Determine the oxidation number of an element (Toolbox K. I and Example K.l). 

The acid strengths and oxidizing abilities of the halogen oxoacids increase with the oxidation number of the halogen. The hypohalous acids, HXO (halogen oxidation number +1), are prepared by direct reaction of the halogen with water. For example, chlorine gas disproportionates in water to produce hypochlorous acid and hydrochloric acid ... 

Nitrogen can be found in compounds with ov datum numbers ranging from —3 to +5. For each of the possible integral oxidation numbers, give one example of n nitrogen compound or ion. 

Like some other d-block metals, such as nickel, iron can form compounds in which its oxidation number is zero. For example, when iron is heated in carbon monoxide, it reacts to form iron pentacarbonyl, Fe(CO)5, a yellow molecular liquid that boils at 103°C. 

If the complex has an overall negative charge (an anionic complex), the suffix -ate is added to the stem of the metal s name. If the symbol of the metal originates from a Latin name (as listed in Appendix 2D), then the Latin stem is used. For example, the symbol for iron is Fe, from the Latin ferrum. Therefore, any anionic complex of iron ends with -ferrate followed by the oxidation number of the metal in Roman numerals ... 

A half-reaction in which the oxidation number of an element is increased. Examples 2 Mg(s) + 02(g) — 2MgO(s) (2, 3) Mg(s) - Mg2+(s) + 2 e. oxidation number The effective charge on an atom in a compound, calculated according to a set of rules (see Toolbox K.l). An increase in oxidation number corresponds to oxidation a decrease corresponds to reduction. 

The citric acid cycle is the final common pathway for the aerobic oxidation of carbohydrate, lipid, and protein because glucose, fatty acids, and most amino acids are metabolized to acetyl-CoA or intermediates of the cycle. It also has a central role in gluconeogenesis, lipogenesis, and interconversion of amino acids. Many of these processes occur in most tissues, but the hver is the only tissue in which all occur to a significant extent. The repercussions are therefore profound when, for example, large numbers of hepatic cells are damaged as in acute hepatitis or replaced by connective tissue (as in cirrhosis). Very few, if any, genetic abnormalities of citric acid cycle enzymes have been reported such ab-normahties would be incompatible with life or normal development. 

To determine oxidation numbers, we assign each valence electron to a specific atom in a compound. This means that the oxidation number of an atom is the charge it would have if the compound were composed of ions. Ionic FeO, for example, would contain Fe cations and 0 anions. Thus, in FeO we assign iron an oxidation number of +2 and oxygen an oxidation number of-2. 

In an ionic compound, each ion is an individual chemical species with its own set of oxidation numbers. For example, we treat ammonium nitrate, NH4 NO3, as NHq cations and NO3 anions. 

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