When between atoms the chemical bond is formed, there is a redistribution of electronic density. As a result, charged particles – ions can be formed. If atom loses electrons, it becomes a cation – a positively charged ion. If it attracts to itself(himself) others electron, becomes anion – a negatively charged ion. And as particles with different charges can be attracted to each other, ions form a chemical bond. At the same time chemical compounds are formed. This communication and is called ionic.
Instruction
1. There is a regularity: ionic communication is formed mainly by atoms of alkaline and alkaline-earth metals, connecting to atoms of halogens. That is first of all look at a chemical formula of substance. Here, for example, table salt – chloride sodium, NaCl. Sodium – alkaline metal, is in the first group of the table of Mendeleyev, chlorine – gas, halogen, is in the seventh group. Therefore, in a molecule of table salt – an ionic chemical bond. Or, for example, fluoric potassium, KF. Potassium - also alkaline metal, and even more active, than sodium. Fluorine – halogen, even more active, than chlorine. Therefore in a molecule of this substance – too an ionic chemical bond.
2. Some physical signs can testify to ionic type of communication. For example, substances with such communication have high temperatures of melting and boiling. At the same chloride sodium they make 800.8 and 1465 degrees, respectively. Solutions of such substances carry electric current. If you find similar properties – know that this substance with ionic communication.
3. It is possible to use values of electronegativity of each chemical element, that is an indicator of that, how easily atom of this element attracts or gives electrons. There are different tables of electronegativity. The scale of Polinga called in honor of the famous American scientist is most widely known. The minimum value of electronegativity on this scale has the most active alkaline metal of frantion (0.7), maximum – the most active halogen fluorine (4.0).
4. To define whether the substance consisting of two elements has ionic type of communication it is necessary to make the following: find electronegativity of these elements (on a scale of Polinga).
5. Subtract smaller value from bigger value. That is establish the difference of elektrootritsatelnosty (EO). For example, for the same table salt it will make: 3.16 (Cl)-0.99 (Na) =2.17. Compare the received size EO to 1.7. If it is more than this value – communication in substance ionic.