Ionization - the main characteristic of the atom.It determines the nature and strength of the chemical bonds that can form atom.Reducing properties of substances (simple) also depend on this characteristic.
term "ionization energy" is sometimes replaced by the term "first ionization potential» (I1), implying that very little energy is needed in order to free an electron from the atom retired when he is in a state of energy, which is called lower.
In particular, the so-called hydrogen energy required to detach an electron from the proton.For atoms with several electrons there is the concept of the second, third, etc.ionization potentials.
ionization energy of the hydrogen atom - is the amount which one term is the energy of the electron, and the other - the potential energy of the system.
In chemistry, the energy of the hydrogen atom is denoted by «Ea», and the amount of potential energy, and the electron energy can be expressed as: Ea = E + T = -Ze / 2.R.
From this expression it is seen that system stability is directly related to the nuclear charge, and the distance between it and the electron.The smaller this distance, the greater the charge of the nucleus, the more they attract, the more stable and sustainable system, the greater the amount of energy you need to spend to break this connection.
Obviously, the level of destruction due to spent energy can be compared to the stability of systems: the more energy, the more stable system.
ionization energy of the atom - (force required to break the bonds in the hydrogen atom) was calculated by experimentation.Today, its value is certain: 13.6 eV (electron volts).Later scholars, also by means of a series of experiments have been able to calculate the energy required to break the bonds of the atoms - electrons in the system, consisting of a single electron and a nucleus of charge, at twice the charge of the hydrogen atom.An experimental way established that in such a case requires 54.4 electron volts.
Known electrostatics laws stipulate that the ionization energy required to break the link between opposites charges (Z and E), provided that they are located at a distance R, fixed (defined) by the equation: T = Ze /R.
This energy is proportional to the charge and, accordingly, is inversely proportional to the distance.This is quite natural: the more charges, the more power connecting them, the stronger the force required to make in order to break the link between them.The same applies to the distance: the smaller it is, the stronger the ionization energy, the more will have to fork to break the connection.
This reasoning explains why the system of atoms with a strong nuclear charge more stable and needs more energy to remove an electron.
question immediately arises: "If the nuclear charge only twice more, why the ionization energy required to detach an electron increases not two, but four times, why it is equal to twice the charge, to take the square (54.4 / 13.6= 4)? ".
This contradiction is explained quite simply.If the charges Z and E are in the system with respect to the mutual state of immobility, the energy (T) is proportional to the charge Z, and they are increasing proportionally.
But in a system where the electron charge e turnover makes a nucleus of charge Z, and Z increases, decreases proportionally to the radius of rotation R: an electron with greater force is attracted to the core.
The conclusion is obvious.In the ionization energy acts nuclear charge, the distance (the radius) from the nucleus to the highest point of the outer electron charge density;the repulsive force between the outer electrons and measure the penetrating power of the electron.