ionic bond is one of three types of interaction between two atoms (the other bonds are the covalent and the metallic). At ionic bond, one of the atoms must be a metal, and the other, an ametal or hydrogen.
The principles that underlie a ionic bond there are just two: the loss of electrons by an atom (high metallic character) and the gain of these electrons by another atom (high nonmetallic character).
See too: What is a valence layer?
Loads of elements for each family
Atom charges follow the principle of octet theory: to achieve stability, the atom needs to have eight electrons in its valence shell.
In the case of metals, this stability is achieved by the loss of electrons; on the other hand, in non-metals, it occurs through the gain of electrons.
Alkali metal family (have 1 electron in the valence shell) = charge +1;
family of alkaline earth metals (have 2 electrons in the valence shell) = charge +2;
Boron family (have 3 electrons in the valence shell) = if metal, charge +3; if nonmetal, charge -3;
Carbon family (have 4 electrons in the valence shell) = if metal, charge +3; if nonmetal, charge -3;
Nitrogen family (have 5 electrons in the valence shell) = if metal, charge +5; if nonmetal, charge -3;
family of chalcogens (have 6 electrons in the valence shell) = if metal, charge +6; if nonmetal, charge -2;
family of halogens (have 7 electrons in the valence shell) = charge -1.
See too: Exceptions to the octet rule
The formula of a substance formed by ionic bond is called ion-formula, which is constructed from the crossing of metal and nonmetal (or hydrogen) charges. In this crossover, the charge of one becomes the atomic index (number of atoms) of the other.
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Representation of the cross to form the ion-formula of an ionic compound
Example
See how the ion-formula of the ionic substance that has aluminum (acronym Al) and oxygen (acronym O) looks like:
Aluminum is a metal that belongs to the boron family, that is, it has a charge +3;
Oxygen is a nonmetal that belongs to the chalcogen family, that is, it has a charge of -2;
Lewis' electronic formula
THE Lewis' electronic formula demonstrates the ionic bond between two or more atoms, that is, it indicates the loss and gain of electrons (represented by spheres) between them. In it we put the valence shell electrons of each element involved.
Let's consider the previous example. In this case, aluminum (positioned on the left) has 3 electrons (boron family), and oxygen (right) has 6 electrons (chalcogen family). Electrons can be placed above, below, to the right or to the left of the element's abbreviation. In metal, they are always on the right side of the acronym. In the non-metal, the left side, preferably, should be without electrons:
The gain and loss of electrons are represented by an arrow that goes from the electron of the metal to the left (empty) side of the ametal acronym:
Characteristics of ionic compounds (substances formed from the ionic bond)
Solids at room temperature;
Higher melting and boiling point than molecular compounds;
They are polar;
suffer dissociation when dissolved in water;
They conduct an electric current if dissolved in water or when in a liquid state (after going through the fusion process);
Generally speaking, they are soluble in water.
By Me. Diogo Lopes
Would you like to reference this text in a school or academic work? Look:
DAYS, Diogo Lopes. "What is an ionic bond?"; Brazil School. Available in: https://brasilescola.uol.com.br/o-que-e/quimica/o-que-e-ligacao-ionica.htm. Accessed on June 28, 2021.
