The Lewis structureproposed by Gilbert Newton Lewis, who first introduced it in 1916, is a graphical representation of the sharing of electrons that occurs in the chemical bonds between atoms of the same or different species. These bonds can be single, double or triple bonds.
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MOLECULES IN THE LEWIS STRUCTURE
In molecules composed of several atoms of the same element and one atom of a different element, it is used as the central atom.
The simplest molecules, including organic molecules, must have a central atom, in some cases the central atom is carbon because it is the most electropositive element, then it is surrounded by the other atoms of the other molecules.
In some cases it is difficult to determine the central atom, usually when all the atoms of the elements in the compound occur more than once or twice.
VALENCE ELECTRONS
The electrons that are represented in the Lewis diagram are the valence electrons of each atom. Valence electrons are the electrons in the last shell of each atom.
Once the valence electrons of each atom are determined, they must be placed in the Lewis model to be structured.
The lone pairs of electrons are located. The atoms must be bonded together. Each bond between 2 atoms is formed by a pair of electrons. As the bond pair is shared between the two atoms, the atom that originally had the lone pair still has an octet; and the other atom now has two more electrons in its last shell.
Organic compounds always have an octet of electrons in their last shell. There are also inorganic compounds, especially in the elements of groups 15 to 18, which have more than 8 electrons in their last shell. Such elements are phosphorus, sulphur, iodine and xenon.
When writing the Lewis structure of an ion, the entire structure is written in square brackets, and the charge is written as an exponent at the top right, outside the brackets.
OCTET RULE
The octet rule o octet rule is a rule that is used in the context of the chemistry. The octet rule defines the property of atoms to complete their last energy level with eight electrons in order to achieve stability. Whether it is a ionic bond, covalent o metalIn the valence shell, atoms will tend to give up or share in order to complete 8 electrons in the valence shell. See all information about the octet rule.