Electron in redox reactions

Jnst as free protons do not exist in solution in acid-base reactions, there are no free electrons in redox reactions. However it is possible to define the activity of electrons relative to a specified standard state and thereby treat electrons as discrete species in equilibrinm calcnlations in the same way as ions and molecules. The standard state of electron activity for this pnrpose is by convention defined with respect to the redox conple made by hydrogen ions and hydrogen gas ... 

The concept of oxidation has been expanded from a simple combination with oxygen to a process in which electrons are transferred. Oxidation cannot take place without reduction, and oxidation numbers can be used to summarize the transfer of electrons in redox reactions. These basic concepts can be applied to the principles of electrochemical cells, electrolysis, and applications of electrochemistry. 

In the above reaction, the exchange of electrons occurs directly between the copper and zinc on the surface of the metal. The transfer of electrons in redox reactions... 

How can you tell when a redox reaction is taking place The answer is that we assign to each atom in a substance a value called an oxidation number (or oxidation state), which indicates whether the atom is neutral, electron-rich, or electron-poor. By comparing the oxidation number of an atom before and after reaction, we can tell whether the atom has gained or lost electrons. Note that oxidation numbers don t necessarily imply ionic charges. They are simply a convenient device to help keep track of electrons in redox reactions. 

The alkaline earth elements in group 2A—Be, Mg, Ca, Sr, Ba, and Ra—are similar to the alkali metals in many respects. They differ, however, in that they have ns2 valence-shell electron configurations and can therefore lose two electrons in redox reactions. Alkaline earth metals are thus powerful reducing agents and form ions with a +2 charge. 

Surface Control of the Number of Electrons in Redox Reaction... 

The Ag+ ion is reduced by [e ] and H to Ag = 360 nm) which undergoes successive reaction with Ag to form Ag, Agj and Ag species. Pulse radiolysis is used to study the reactions of Ag atonls especially as they serve as a pool for electrons in redox reactions and the reduction " of HjO. The mechanism of reduction of Ag(I)-ammine complexes is similar to that of Ag" ". 

The first step in this system is to assign an oxidation number to each atom in the reaction equation. As you become better acquainted with the procedure, you will gain a better understanding of what the numbers signify, but for now, just think of them as tools for keeping track of the flow of electrons in redox reactions. Oxidation numbers are also called oxidation states. 

Oxidation number A tool for keeping track of the flow of electrons in redox reactions (also called oxidation state). 

To keep track of electrons in redox reactions, it is useful to assign oxidation numbers to the reactants and products. An atom s oxidation number, also called oxidation state, signifies the number of charges the atom would have in a molecule (or an ionic compound) if electrons were transferred completely. For example, we can rewrite the above equations for the formation of HCl and SO2 as follows ... 

The oxidation number of an element in a compound is a number assigned to that element that reflects how its electrons are involved in making up the compound. For example, if an atom of an element loses one electron and forms a +1 cation, the oxidation number of that element in a compound is +1. If an atom of an element gains one electron and forms a -1 ion, the oxidation number is -1. This is also often referred to as the oxidation state of an element. It is a sort of book-keeping concept that is used in some naming schemes, as well as to track electrons in redox reactions. Thus it is a concept of some importance. 

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