Metals are important and in many ways unique chemical elements.Virtually all these characteristic properties such as good electrical conductivity, luster, thermal conductivity.At the same time, among them there are some groups whose characteristics differ materially.Some of these distinguishing features formed the basis of such concepts as "the activity of a number of metals."
metals are known to be characterized by the fact that during chemical reactions give free electrons.From the flow rate of the process depends on their electrode potential.In turn, these values were the basis to form a voltage range of metals - with respect to the conditional sequence that characterizes the ability of a cell to react with certain substances.
conditional place each item in this series stems from the fact that at different temperature and composition of the solution, they behave more or less active.Average values are displayed at a solution temperature of 25 degrees Celsius and a pressure of one atmosphere gases.It is under these conditions a series of metal activity takes the form which is familiar to everyone from school chemistry course.
Of all these indicators follows a list of the most important properties.First, the voltage range of metals can help us predict how they will behave in certain elements during the reaction, those that are left in this sequence, would replace the ones that are to the right of them.Secondly, if the element is left hydrogen electrode potential is made to accept zero, it can displace it from the acid solution.This applies in particular to lithium, sodium, potassium and other alkali elements.Finally, the third, the number of active metals is of great help in creating the galvanic cells: the further apart the elements in it, the higher electric potential arises between them.
It is focusing on what metals displace each other from solutions of salts, and made his famous table of outstanding Russian scientist Beketov.This table was slightly corrected later served as the basis and the fact that for over a hundred years known as the "number of active metals."
Curiously enough to compare certain patterns arising from the Periodic Table and the sequence.Thus, based on the work of Mendeleev, potassium should be more potent than sodium and lithium, but the voltage range gives a different picture.The main reason for this contradiction lies in the grounds, which form the basis of these sequences.Periodic system reflects the change in the value of the ionization energy of the atoms and the sequence Beketov - what kind of work needs to be done to translate this or that element of the solid state to a set of ions in an aqueous solution of the idea.
