ionization
The phenomenon of ionization is the separation of one or more electrons from atoms or molecules to which they belong, who are charged accordingly positively. Ionization does not result in generation of net electrical charge, but a provision of electric charges for subsequent recombination and reactions within the irradiated field. In physics, fully ionized atomic nuclei, such as alpha particles, charged particles are commonly known. Ionization is usually performed by applying high energy to the atoms in the form of electric potential or radiation. An ionized gas is called plasma. The negatively charged ions are known as anions (which are attracted to the anode) and the positively charged are called cations (and are attracted to the cathode). Ions can be monovalent (indicated by a + or -), divalent (with two + or -) and trivalent (three +). Then ions are divided into monoatomic and polyatomic. For single atoms in a vacuum, there is a physical constant associated with the ionization process. The energy required to remove electrons from an atom is called ionization energy or ionization potential.
The danger of ionizing radiation
Ionizing radiation produces damage: a consequence of the ionization produced by radiation are generated within the new cells, molecules or fragments of molecules very aggressive from the biochemical point of view, capable of irreparably damage at the molecular structures responsible for cell function, or integrity the genetic heritage. The damage can be immediate if radiation dose is likely to directly inhibit the functions of the cell body or bodies to which they belong, or delayed in time in case of damage to the genes of the cell. The amount of radiation energy needed to produce damage, even very serious, is, in absolute terms, very small: nothing compared to the energies involved in the most common tasks of daily life, such as heating a saucepan of water , ol 'pile driving a nail to the wall. For example, the energy of a beam of ionizing radiation can induce, if consumption of the whole body, the death of the irradiated within thirty days with a probability of 50% (an effect therefore of the utmost gravity) would, if fully converted into heat energy, raising the temperature of the body of a thousandth of a degree centigrade, quite negligible. In comparison, the threshold for the onset of physiological effects due to heating by non-ionizing radiation (radio waves, microwaves, ...) is 1 ° C rise in body temperature or by irradiation of the party concerned. Therefore, the risk of ionizing radiation is not due to their high energy content in absolute terms, but the extreme effectiveness of their destructive action against the molecular structure of organized living matter.
The
The ionic bond ionic bond is a type of bond that can take place only between different atoms.
We know that many atoms can be ions, for purchase or loss of electrons: some
, which have low ionization energy, they can easily give cations losing a certain number of electrons, thereby taking an equal number of positive charges. Other
, with high electron affinity, can make a number of anions by accepting electrons, thereby taking an equal number of negative charges. Anions and cations are attracted by electrostatic interaction: this interaction is called ionic bonding. All atoms of 1, 2 and 3 group create ionic bonds with the exception of hydrogen (H) that will create the covalent bond (a bond formed by a pair of electrons shared between two atoms), then the elements of the 5th, 6th and 7th group will buy 3 respectively, 2.1 electrons, these atoms gain electrons because they are very electronegative and tend to attract to that if the electrons, while the 1st, 2nd and 3rd group to become stable electron must give respectively 1,2,3.
ionic compounds are characterized by high melting points and ability to conduct electricity in molten state and in aqueous solution, tend to be soluble in water and crystallize.
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