Elements oxidation numbers

Next, rule 10 is used for determining all oxidation numbers of all elements that rules 1 through 8 do not cover (this must be all but one element in a formula), and then assigning the remaining elements oxidation numbers, knowing that the total must add up to either zero or the ionic charge. 

Element Oxidation Number as Reactant Oxidation Number as Product Change in Oxidation Number Oxidation or Reduction... 

Element Oxidation Number Complex ion of which element is a part... 

The maximum oxidation number of any atom in any of its compounds is equal to its periodic group number, with a few exceptions. The coinage metals have the following maximum oxidation numbers Cu, +2 Ag, +2 and Au, +3. Some of the noble gases (group 0) have positive oxidation numbers. Some lanthanide and actinide element oxidation numbers exceed 3, their nominal group number. 

Oxidation numbers of an element Oxidation numbers of an element... 

The following elements nearly always have the Element Oxidation number... 

Oxidation and reduction are opposite reactions. An oxidizing agent is the element in the reaction that oxidizes another element, while at the same time being reduced itself. A reducing agent is the element in the reaction that reduces another element while at the same time being oxidized itself. In redox reactions, the total charge of the elements oxidation numbers will be equal on both sides of the equation. 

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—). 

Thorium [7440-29-1], a naturally occurring radioactive element, atomic number 90, atomic mass 232.0381, is the second element of the actinide ( f) series (see Actinides AND transactinides Radioisotopes). Discovered in 1828 in a Norwegian mineral, thorium was first isolated in its oxide form. For the light actinide elements in the first half of the. series, there is a small energy difference between and 5/ 6d7 electronic configurations. Atomic spectra... 

Other methods for indicating or implying the presence of an atom in a nonstandard valence state have been used, especially the use of the prefix hydro e.g. 108). Such methods are sometimes convenient for simple molecules, but they are difficult to apply generally. A more general method that has seen extensive use utilizes the italicized symbol for the element with a superscript Roman numeral to indicate the valence (e.g. 109). This method has been objected to, however, because of ambiguity the superscript Roman number is also used to indicate oxidation number in inorganic compounds, and italicized atomic symbols are customarily used as locants for substituents. The A convention is a modification of the principle of this method, and avoids the objection. It was made a Provisional Recommendation of lUPAC in 1981. 

Notice that this generalization follows naturally from the method of calculating oxidation numbers outlined in Table 2.5. In a C—C bond one electron is assigned to one carbon, the second electron to the other. In a bond between carbon and some other element, none of the electrons in that bond ar e assigned to car bon when the element is more electronegative than carbon both are assigned to carbon when the element is less electronegative than carbon. 

The concept of oxidation number is used to simplify the electron bookkeeping in redox reactions. For a monatomic ion (e.g., Na+, S2 ), the oxidation number is, quite simply, the charge of the ion (+1, —2). In a molecule or polyatomic ion, the oxidation number of an element is a pseudo-charge obtained in a rather arbitrary way, assigning bonding electrons to the atom with the greater attraction for electrons. 

The oxidation number of an element in a monatomic ion is equal to the charge of that ion. In the ionic compound NaCl, sodium has an oxidation number of +1, chlorine an oxidation number of — 1. The oxidation numbers of aluminum and oxygen in A1203 (Al3+, O2- ions) are +3 and —2, respectively. 

Certain elements have the same oxidation number in all or almost all their compounds. The Group 1 metals always exist as +1 ions in their compounds and hence are assigned an oxidation number of +1. By the same token, Group 2 elements always have oxidation numbers of +2 in their compounds. Fluorine always has an oxidation number of — 1. 

Strategy First look for elements whose oxidation number is always or almost always the same (rule 3). Then solve for the oxidation number of phosphorus, applying rule 4. 

These definitions are of course compatible with the interpretation of oxidation and reduction in terms of loss and gain of electrons. An element that loses electrons must increase in oxidation number. The gain of electrons always results in a decrease in oxidation number. 

An easy way to recognize a redox equation is to note changes in oxidation number of two different elements. The net ionic equation... 

For the present, we will limit ourselves to molecules containing hydrogen and/or oxygen along with the element to which we wish to assign an oxidation number. The rules we will utilize are as follows ... 

First, we assign oxidation numbers to each element, using rules 1-5. We find... 

---